diff --git a/backend/README.md b/backend/README.md
new file mode 100644
index 0000000..2adad4e
--- /dev/null
+++ b/backend/README.md
@@ -0,0 +1,330 @@
+# svg-service backend
+
+Backend for SVG scheme upload, draft editing, pricing, publish preview, and publish lifecycle.
+
+## Stack
+
+- Python 3.11
+- FastAPI
+- SQLAlchemy async
+- PostgreSQL 16
+- Docker Compose
+
+## Runtime
+
+Default backend port: `9020`
+
+Health check:
+
+- `GET /healthz`
+
+Main API prefix:
+
+- `/api/v1`
+
+Auth header:
+
+- `X-API-Key`
+
+Default local admin key:
+
+- `admin-local-dev-key`
+
+## Core lifecycle
+
+The backend works with a scheme lifecycle:
+
+1. Upload SVG
+2. Normalize and persist structure
+3. Work in current draft
+4. Create / update pricing
+5. Build pricing snapshot
+6. Inspect publish preview / readiness
+7. Publish current draft
+8. If editing is needed after publish, create or ensure a new draft again
+
+## Main concepts
+
+### Scheme
+Top-level business entity.
+
+### Scheme version
+Concrete version of the scheme.  
+A version can be `draft` or `published`.
+
+### Current version
+The version referenced by the scheme registry as active current.
+
+### Draft
+Editable current version.  
+All editor mutations and draft pricing operations must target a current draft version only.
+
+### Published version
+Non-editable current version.  
+If current version is published, editor flow must first create or ensure a new draft.
+
+### Upload artifacts
+Stored technical artifacts, including:
+
+- original svg
+- sanitized svg
+- normalized json
+- display svg
+- publish preview json
+
+## Editor entry flow
+
+Use this flow from frontend or operator scripts.
+
+### 1. Inspect editor state
+
+`GET /api/v1/schemes/{scheme_id}/editor/context`
+
+Response tells whether:
+
+- current version is draft
+- editor is available
+- a new draft should be created
+- recommended action is `use_current_draft` or `create_draft`
+
+### 2. Ensure editable draft
+
+`POST /api/v1/schemes/{scheme_id}/draft/ensure`
+
+Behavior:
+
+- if current version is already draft: returns it with `created=false`
+- if current version is published: clones current version into a new current draft and returns it with `created=true`
+
+Returned `scheme_version_id` must be reused as:
+
+- `expected_scheme_version_id`
+
+for draft reads and mutations.
+
+## Optimistic concurrency
+
+Mutable draft flows support optimistic concurrency through query params:
+
+- `expected_current_scheme_version_id`
+- `expected_scheme_version_id`
+
+These guards prevent frontend/editor from mutating a stale draft after another version switch.
+
+Typical typed conflict payload:
+
+- `stale_current_version`
+- `stale_draft_version`
+- `draft_not_editable`
+- `publish_not_ready`
+
+## Main operator routes
+
+## System
+
+- `GET /healthz`
+- `GET /api/v1/ping`
+- `GET /api/v1/db/ping`
+- `GET /api/v1/manifest`
+
+## Uploads
+
+- `POST /api/v1/schemes/upload`
+- `GET /api/v1/uploads`
+- `GET /api/v1/uploads/{upload_id}`
+- `GET /api/v1/uploads/{upload_id}/normalized`
+
+## Scheme registry
+
+- `GET /api/v1/schemes`
+- `GET /api/v1/schemes/{scheme_id}`
+- `GET /api/v1/schemes/{scheme_id}/current`
+- `GET /api/v1/schemes/{scheme_id}/versions`
+- `POST /api/v1/schemes/{scheme_id}/versions`
+- `GET /api/v1/schemes/{scheme_id}/publish/validation`
+- `GET /api/v1/schemes/{scheme_id}/draft/publish-readiness`
+- `POST /api/v1/schemes/{scheme_id}/publish`
+- `POST /api/v1/schemes/{scheme_id}/unpublish`
+- `POST /api/v1/schemes/{scheme_id}/rollback`
+
+## Editor / draft
+
+- `GET /api/v1/schemes/{scheme_id}/editor/context`
+- `POST /api/v1/schemes/{scheme_id}/draft/ensure`
+- `GET /api/v1/schemes/{scheme_id}/draft/summary`
+- `GET /api/v1/schemes/{scheme_id}/draft/structure`
+- `GET /api/v1/schemes/{scheme_id}/draft/validation`
+- `GET /api/v1/schemes/{scheme_id}/draft/compare-preview`
+- `GET /api/v1/schemes/{scheme_id}/draft/seats/records/{seat_record_id}`
+- `GET /api/v1/schemes/{scheme_id}/draft/sectors/records/{sector_record_id}`
+- `GET /api/v1/schemes/{scheme_id}/draft/groups/records/{group_record_id}`
+- `POST /api/v1/schemes/{scheme_id}/draft/sectors`
+- `POST /api/v1/schemes/{scheme_id}/draft/groups`
+- `DELETE /api/v1/schemes/{scheme_id}/draft/sectors/records/{sector_record_id}`
+- `DELETE /api/v1/schemes/{scheme_id}/draft/groups/records/{group_record_id}`
+- `PATCH /api/v1/schemes/{scheme_id}/draft/seats/records/{seat_record_id}`
+- `POST /api/v1/schemes/{scheme_id}/draft/seats/bulk`
+- `PATCH /api/v1/schemes/{scheme_id}/draft/sectors/records/{sector_record_id}`
+- `PATCH /api/v1/schemes/{scheme_id}/draft/groups/records/{group_record_id}`
+- `POST /api/v1/schemes/{scheme_id}/draft/repair-references`
+
+## Pricing
+
+- `GET /api/v1/schemes/{scheme_id}/pricing`
+- `POST /api/v1/schemes/{scheme_id}/pricing/categories`
+- `PUT /api/v1/schemes/{scheme_id}/pricing/categories/{pricing_category_id}`
+- `DELETE /api/v1/schemes/{scheme_id}/pricing/categories/{pricing_category_id}`
+- `POST /api/v1/schemes/{scheme_id}/pricing/rules`
+- `PUT /api/v1/schemes/{scheme_id}/pricing/rules/{price_rule_id}`
+- `DELETE /api/v1/schemes/{scheme_id}/pricing/rules/{price_rule_id}`
+
+## Pricing diagnostics
+
+- `GET /api/v1/schemes/{scheme_id}/pricing/coverage`
+- `GET /api/v1/schemes/{scheme_id}/pricing/unpriced-seats`
+- `GET /api/v1/schemes/{scheme_id}/pricing/explain/{seat_id}`
+- `GET /api/v1/schemes/{scheme_id}/pricing/rules/diagnostics`
+
+## Publish preview
+
+- `POST /api/v1/schemes/{scheme_id}/draft/pricing/snapshot`
+- `GET /api/v1/schemes/{scheme_id}/draft/publish-preview`
+- `POST /api/v1/schemes/{scheme_id}/draft/remap/preview`
+- `POST /api/v1/schemes/{scheme_id}/draft/remap/apply`
+
+## Structure read model
+
+- `GET /api/v1/schemes/{scheme_id}/current/sectors`
+- `GET /api/v1/schemes/{scheme_id}/current/groups`
+- `GET /api/v1/schemes/{scheme_id}/current/seats`
+- `GET /api/v1/schemes/{scheme_id}/current/seats/{seat_id}/price`
+- `GET /api/v1/schemes/{scheme_id}/current/svg`
+- `GET /api/v1/schemes/{scheme_id}/current/svg/display`
+- `GET /api/v1/schemes/{scheme_id}/current/svg/display/meta`
+
+## Test mode
+
+- `GET /api/v1/schemes/{scheme_id}/test/seats/{seat_id}`
+
+## Audit
+
+- `GET /api/v1/schemes/{scheme_id}/audit`
+
+## Admin / ops
+
+- `GET /api/v1/admin/schemes/{scheme_id}/current/artifacts`
+- `GET /api/v1/admin/schemes/{scheme_id}/current/validation`
+- `POST /api/v1/admin/schemes/{scheme_id}/current/display/regenerate`
+- `POST /api/v1/admin/display/backfill`
+- `GET /api/v1/admin/artifacts/publish-preview/audit`
+- `POST /api/v1/admin/artifacts/publish-preview/cleanup`
+
+## Typical local flow
+
+## 1. Read current version
+
+Use:
+
+`GET /api/v1/schemes/{scheme_id}/current`
+
+## 2. Ensure draft
+
+Use:
+
+`POST /api/v1/schemes/{scheme_id}/draft/ensure`
+
+Store returned:
+
+- `scheme_version_id`
+
+## 3. Read draft state
+
+Use:
+
+- `GET /draft/summary?expected_scheme_version_id=...`
+- `GET /draft/structure?expected_scheme_version_id=...`
+- `GET /draft/validation?expected_scheme_version_id=...`
+- `GET /draft/compare-preview?expected_scheme_version_id=...`
+
+## 4. Perform editor mutations
+
+Pass:
+
+- `expected_scheme_version_id={draft_scheme_version_id}`
+
+on every mutation route.
+
+## 5. Inspect pricing quality
+
+Use:
+
+- `GET /pricing/coverage`
+- `GET /pricing/unpriced-seats`
+- `GET /pricing/explain/{seat_id}`
+- `GET /pricing/rules/diagnostics`
+
+## 6. Create pricing snapshot
+
+Use:
+
+`POST /draft/pricing/snapshot?expected_scheme_version_id=...`
+
+## 7. Inspect readiness
+
+Use:
+
+`GET /draft/publish-readiness?expected_scheme_version_id=...`
+
+## 8. Publish
+
+Use:
+
+`POST /publish?expected_scheme_version_id=...`
+
+## Typed error expectations
+
+Examples of stable typed errors already used in the service:
+
+### Draft concurrency/state
+- `stale_current_version`
+- `stale_draft_version`
+- `draft_not_editable`
+
+### Editor validation
+- `duplicate_seat_id`
+- `duplicate_seat_id_in_payload`
+- `duplicate_sector_id`
+- `duplicate_group_id`
+- `duplicate_sector_element_id`
+- `duplicate_group_element_id`
+- `unknown_sector_id`
+- `unknown_group_id`
+- `unknown_sector_ids`
+- `unknown_group_ids`
+- `unknown_target_sector_id`
+- `unknown_target_group_id`
+- `remap_filter_required`
+
+### Pricing / publish
+- `invalid_amount`
+- `publish_not_ready`
+
+## Draft summary semantics
+
+`GET /draft/summary` is the compact route for editor bootstrap.
+
+It returns:
+
+- current draft counters
+- validation summary
+- structure diff summary
+- publish readiness summary
+
+This route is intended for frontend side panels / header status / quick preflight.
+
+## Notes
+
+- Draft-only routes must not mutate a published current version.
+- Published current version should require `draft/ensure` before any editor mutation.
+- Publish readiness can fail even if validation passes, for example when pricing snapshot is missing.
+- `api-map.md` and `smoke-regression.md` must be updated together with route changes.
diff --git a/backend/app/api/routes/structure.py b/backend/app/api/routes/structure.py
index 66213a6..7f57e96 100644
--- a/backend/app/api/routes/structure.py
+++ b/backend/app/api/routes/structure.py
@@ -244,7 +244,7 @@ async def get_effective_seat_price(scheme_id: str, seat_id: str, role: str = Dep
         matched_rule_level=matched_rule_level,
         matched_target_ref=rule["target_ref"],
         pricing_category_id=rule["pricing_category_id"],
-        amount=rule["amount"],
+        amount=str(rule["amount"]),
         currency=rule["currency"],
     )
 
diff --git a/backend/docs/api-map.md b/backend/docs/api-map.md
index e0100b7..6914f7c 100644
--- a/backend/docs/api-map.md
+++ b/backend/docs/api-map.md
@@ -21,6 +21,7 @@
 - GET /api/v1/schemes/{scheme_id}/versions
 - POST /api/v1/schemes/{scheme_id}/versions
 - GET /api/v1/schemes/{scheme_id}/publish/validation
+- GET /api/v1/schemes/{scheme_id}/draft/publish-readiness
 - POST /api/v1/schemes/{scheme_id}/publish
 - POST /api/v1/schemes/{scheme_id}/unpublish
 - POST /api/v1/schemes/{scheme_id}/rollback
@@ -58,7 +59,6 @@
 ## app/api/routes/publish.py
 - POST /api/v1/schemes/{scheme_id}/draft/pricing/snapshot
 - GET /api/v1/schemes/{scheme_id}/draft/publish-preview
-- GET /api/v1/schemes/{scheme_id}/draft/publish-readiness
 - POST /api/v1/schemes/{scheme_id}/draft/remap/preview
 - POST /api/v1/schemes/{scheme_id}/draft/remap/apply
 
@@ -94,4 +94,4 @@
 - This file is an operational route index, not a generated OpenAPI export.
 - Update this map in the same change set when adding, removing, renaming, or moving routes.
 - Query guards such as expected_current_scheme_version_id / expected_scheme_version_id are part of the operational contract for optimistic concurrency on mutable flows.
-- Draft/editor routes may legally return 409 draft_not_editable when current version is already published and no editable draft exists yet.
+- Draft editor flow starts from editor/context and draft/ensure, not from direct blind mutation calls.
diff --git a/backend/docs/smoke-regression.md b/backend/docs/smoke-regression.md
index c2e0c98..c5a7851 100644
--- a/backend/docs/smoke-regression.md
+++ b/backend/docs/smoke-regression.md
@@ -31,19 +31,78 @@ export SCHEME_ID="82086336d385427f9d56244f9e1dd772"
 - GET /api/v1/schemes/{scheme_id}/current -> 200
 - GET /api/v1/schemes/{scheme_id}/versions -> 200
 
-## 3. Structure read model
+Validate:
+- scheme_id is stable
+- current version exists
+- version list contains current version
+- status and counts are consistent
+
+## 3. Editor entry flow
+
+- GET /api/v1/schemes/{scheme_id}/editor/context -> 200
+- POST /api/v1/schemes/{scheme_id}/draft/ensure -> 200
+
+Validate:
+- editor context returns current_scheme_version_id
+- editor context distinguishes draft vs published state correctly
+- ensure endpoint is idempotent on current draft
+- ensure endpoint creates a new draft from published current when needed
+- returned scheme_version_id is reusable as expected_scheme_version_id
+
+## 4. Draft read model
+
+Using current draft version id from draft/ensure:
+
+- GET /api/v1/schemes/{scheme_id}/draft/summary?expected_scheme_version_id={draft_version_id} -> 200
+- GET /api/v1/schemes/{scheme_id}/draft/structure?expected_scheme_version_id={draft_version_id} -> 200
+- GET /api/v1/schemes/{scheme_id}/draft/validation?expected_scheme_version_id={draft_version_id} -> 200
+- GET /api/v1/schemes/{scheme_id}/draft/compare-preview?expected_scheme_version_id={draft_version_id} -> 200
+
+Validate:
+- summary returns total_seats / total_sectors / total_groups
+- summary returns validation_summary / structure_diff_summary / publish_readiness
+- structure returns lists for seats / sectors / groups
+- validation is deterministic
+- compare preview returns stable diff structure
+- stale expected_scheme_version_id returns typed 409 conflict
+
+## 5. Draft entity reads
+
+- GET /api/v1/schemes/{scheme_id}/draft/seats/records/{seat_record_id} -> 200
+- GET /api/v1/schemes/{scheme_id}/draft/sectors/records/{sector_record_id} -> 200
+- GET /api/v1/schemes/{scheme_id}/draft/groups/records/{group_record_id} -> 200
+
+Validate:
+- record endpoints return exact draft entities
+- unknown record id returns 404
+- stale expected_scheme_version_id returns typed 409 conflict
+
+## 6. Structure read model
 
 - GET /api/v1/schemes/{scheme_id}/current/sectors -> 200
 - GET /api/v1/schemes/{scheme_id}/current/groups -> 200
 - GET /api/v1/schemes/{scheme_id}/current/seats -> 200
 
-## 4. SVG / display pipeline
+Validate:
+- total counts are non-negative
+- known sample scheme returns expected object lists
+- seats contain seat_id / sector_id / group_id contract where applicable
+
+## 7. SVG / display pipeline
 
 - GET /api/v1/schemes/{scheme_id}/current/svg -> 200
 - GET /api/v1/schemes/{scheme_id}/current/svg/display -> 200
 - GET /api/v1/schemes/{scheme_id}/current/svg/display/meta -> 200
+- GET /api/v1/schemes/{scheme_id}/current/svg/display?mode=optimized -> 200 or explicit controlled failure
+- GET /api/v1/schemes/{scheme_id}/current/svg/display/meta?mode=optimized -> 200 or explicit controlled failure
 
-## 5. Pricing read model / diagnostics
+Validate:
+- response content type for svg endpoints is image/svg+xml
+- meta returns scheme_id, scheme_version_id, view_box, width, height
+- no 500 on passthrough mode
+- unsupported mode returns 422
+
+## 8. Pricing read model
 
 - GET /api/v1/schemes/{scheme_id}/pricing -> 200
 - GET /api/v1/schemes/{scheme_id}/pricing/coverage -> 200
@@ -51,71 +110,113 @@ export SCHEME_ID="82086336d385427f9d56244f9e1dd772"
 - GET /api/v1/schemes/{scheme_id}/pricing/explain/{seat_id} -> 200
 - GET /api/v1/schemes/{scheme_id}/pricing/rules/diagnostics -> 200
 - GET /api/v1/schemes/{scheme_id}/current/seats/{seat_id}/price -> 200 for priced seat
-- GET /api/v1/schemes/{scheme_id}/test/seats/{seat_id} -> 200 for priced and unpriced seat
-
-## 6. Editor entry workflow
-
-- GET /api/v1/schemes/{scheme_id}/editor/context -> 200 always
-- if context.needs_new_draft=true -> POST /api/v1/schemes/{scheme_id}/draft/ensure -> 200
-- after ensure -> GET /api/v1/schemes/{scheme_id}/editor/context -> 200 and editable=true
+- GET /api/v1/schemes/{scheme_id}/test/seats/{seat_id} -> 200 for known seat
 
 Validate:
-- published current version does not break editor bootstrap
-- ensure returns created_new_draft=true when current was published
-- ensure returns created_new_draft=false when current was already draft
+- pricing bundle contains categories and rules arrays
+- coverage values are internally consistent
+- unpriced seats list explains reason_code / reason_message
+- explain endpoint shows matched rule for priced seat and null for unpriced seat
+- diagnostics returns orphan/active rule visibility
+- test seat preview explains selectable / has_price state
+- priced test seat amount is serialized as string
 
-## 7. Draft editor read model
+## 9. Draft mutations and validation guards
 
-- GET /api/v1/schemes/{scheme_id}/draft/summary -> 200 when current version is draft
-- GET /api/v1/schemes/{scheme_id}/draft/structure -> 200 when current version is draft
-- GET /api/v1/schemes/{scheme_id}/draft/validation -> 200 when current version is draft
-- GET /api/v1/schemes/{scheme_id}/draft/compare-preview -> 200 when current version is draft
-- GET /api/v1/schemes/{scheme_id}/draft/seats/records/{seat_record_id} -> 200
-- GET /api/v1/schemes/{scheme_id}/draft/sectors/records/{sector_record_id} -> 200
-- GET /api/v1/schemes/{scheme_id}/draft/groups/records/{group_record_id} -> 200
+For current draft version:
 
-## 8. Draft mutations
-
-- POST /api/v1/schemes/{scheme_id}/draft/sectors -> 200 or typed 422 conflict
-- POST /api/v1/schemes/{scheme_id}/draft/groups -> 200 or typed 422 conflict
-- PATCH /api/v1/schemes/{scheme_id}/draft/seats/records/{seat_record_id} -> 200 or typed 422 validation error
-- POST /api/v1/schemes/{scheme_id}/draft/seats/bulk -> 200 or typed 422 validation error
-- PATCH /api/v1/schemes/{scheme_id}/draft/sectors/records/{sector_record_id} -> 200
-- PATCH /api/v1/schemes/{scheme_id}/draft/groups/records/{group_record_id} -> 200
+- POST /api/v1/schemes/{scheme_id}/draft/sectors -> 200 or 422
+- POST /api/v1/schemes/{scheme_id}/draft/groups -> 200 or 422
+- PATCH /api/v1/schemes/{scheme_id}/draft/seats/records/{seat_record_id} -> 200 or 422
+- POST /api/v1/schemes/{scheme_id}/draft/seats/bulk -> 200 or 422
+- POST /api/v1/schemes/{scheme_id}/draft/remap/preview -> 200 or 422
+- POST /api/v1/schemes/{scheme_id}/draft/remap/apply -> 200 or 422
 - POST /api/v1/schemes/{scheme_id}/draft/repair-references -> 200
-- POST /api/v1/schemes/{scheme_id}/draft/remap/preview -> 200 or typed 422 validation error
-- POST /api/v1/schemes/{scheme_id}/draft/remap/apply -> 200 or typed 422 validation error
 
-## 9. Publish preview / readiness
+Validate:
+- duplicate ids return typed 422
+- duplicate element binding returns typed 422
+- unknown sector/group references return typed 422
+- remap without filters returns typed 422
+- stale expected_scheme_version_id returns typed 409
+- published current version rejects draft mutations with typed draft_not_editable conflict
+
+## 10. Draft publish preview
 
-- GET /api/v1/schemes/{scheme_id}/publish/validation -> 200
-- GET /api/v1/schemes/{scheme_id}/draft/publish-readiness -> 200 when current version is draft
 - POST /api/v1/schemes/{scheme_id}/draft/pricing/snapshot -> 200 when scheme is in draft
 - GET /api/v1/schemes/{scheme_id}/draft/publish-preview?refresh=true -> 200
 - GET /api/v1/schemes/{scheme_id}/draft/publish-preview -> 200
+- GET /api/v1/schemes/{scheme_id}/draft/publish-preview?refresh=true&baseline_scheme_version_id={published_version_id} -> 200
 
-## 10. Publish lifecycle
+Validate:
+- refresh and cached read both succeed
+- preview summary contains is_publishable / has_structure_changes / has_artifacts / snapshot_available
+- pricing_coverage is internally consistent
+- baseline override returns override strategy when explicit baseline is provided
+- preview retention does not grow unbounded for same version+variant
 
-- POST /api/v1/schemes/{scheme_id}/publish -> 200 when draft is ready
-- POST /api/v1/schemes/{scheme_id}/publish with stale expected_scheme_version_id -> 409
-- POST /api/v1/schemes/{scheme_id}/unpublish -> 200
-- POST /api/v1/schemes/{scheme_id}/rollback -> 200
+## 11. Publish readiness and publish flow
 
-## 11. Admin / ops
+For current draft version:
+
+- GET /api/v1/schemes/{scheme_id}/draft/publish-readiness -> 200
+- POST /api/v1/schemes/{scheme_id}/publish?expected_scheme_version_id={draft_version_id} -> 200 or 409
+
+Validate:
+- readiness explicitly shows snapshot_available and pricing gate state
+- publish with stale expected version returns typed 409
+- publish without draft state returns typed 409
+- publish success updates current status to published
+- audit trail contains scheme.published event
+
+## 12. Admin / ops
 
 - GET /api/v1/admin/schemes/{scheme_id}/current/artifacts -> 200
 - GET /api/v1/admin/schemes/{scheme_id}/current/validation -> 200
 - GET /api/v1/admin/artifacts/publish-preview/audit -> 200
 - POST /api/v1/admin/artifacts/publish-preview/cleanup?dry_run=true -> 200
 
-## 12. Audit trail
+Optional:
+- POST /api/v1/admin/schemes/{scheme_id}/current/display/regenerate?mode=passthrough -> 200
+- POST /api/v1/admin/display/backfill?mode=passthrough&limit=10&only_missing=true -> 200
+
+Validate:
+- audit endpoint does not report orphan files or missing files for DB rows in normal state
+- validation report is readable and deterministic
+- admin routes do not produce 500 for healthy scheme state
+
+## 13. Audit trail
 
 - GET /api/v1/schemes/{scheme_id}/audit -> 200
 
-## 13. Fail criteria
+Validate:
+- recent publish preview / pricing / version / publish events are present when corresponding operations were run
+- audit total is non-negative
+- event payloads stay JSON-serializable
 
-Regression is considered failed if:
+## 14. Fail criteria
+
+Regression is considered failed if any of the following happen:
+
+- health or db ping fails
 - any stable read endpoint returns 500
-- published current version cannot be converted to draft through ensure flow
-- draft editor summary/read endpoints return inconsistent data
-- publish-state mutation guard is bypassed
+- passthrough display endpoint fails on known-good sample
+- publish preview refresh or cached read returns 500
+- publish readiness returns 500
+- editor context or draft ensure returns 500
+- draft summary / structure / validation / compare-preview returns 500
+- pricing bundle or diagnostics contract changes unexpectedly
+- admin audit/cleanup endpoints fail on healthy environment
+- artifact retention grows without bound for repeated preview refresh on same variant
+
+## 15. Operator note
+
+Run this checklist after:
+- schema changes
+- pricing schema/repository refactors
+- artifact lifecycle changes
+- display pipeline changes
+- route reorganization
+- startup/import/config changes
+- draft lifecycle changes
+- publish readiness changes
diff --git a/backend/scripts/smoke_regression.sh b/backend/scripts/smoke_regression.sh
new file mode 100755
index 0000000..654e541
--- /dev/null
+++ b/backend/scripts/smoke_regression.sh
@@ -0,0 +1,201 @@
+#!/usr/bin/env bash
+set -Eeuo pipefail
+
+API_URL="${API_URL:-http://127.0.0.1:9020}"
+API_KEY="${API_KEY:-admin-local-dev-key}"
+SCHEME_ID="${SCHEME_ID:-82086336d385427f9d56244f9e1dd772}"
+
+WORKDIR="$(mktemp -d)"
+trap 'rm -rf "$WORKDIR"' EXIT
+
+HDR_AUTH=(-H "X-API-Key: ${API_KEY}")
+HDR_JSON=(-H "Content-Type: application/json")
+
+step() {
+  echo
+  echo "===== $1 ====="
+}
+
+fail() {
+  echo
+  echo "[FAIL] $1" >&2
+  exit 1
+}
+
+request() {
+  local name="$1"
+  local method="$2"
+  local url="$3"
+  local expected="$4"
+  local body="${5:-}"
+  local outfile="${WORKDIR}/${name}.body"
+  local codefile="${WORKDIR}/${name}.code"
+
+  if [[ -n "$body" ]]; then
+    curl -sS \
+      -X "$method" \
+      "${HDR_AUTH[@]}" \
+      "${HDR_JSON[@]}" \
+      -o "$outfile" \
+      -w "%{http_code}" \
+      "$url" \
+      --data "$body" > "$codefile"
+  else
+    curl -sS \
+      -X "$method" \
+      "${HDR_AUTH[@]}" \
+      -o "$outfile" \
+      -w "%{http_code}" \
+      "$url" > "$codefile"
+  fi
+
+  local code
+  code="$(cat "$codefile")"
+
+  echo "[$method] $url -> $code"
+  cat "$outfile"
+  echo
+
+  if [[ "$code" != "$expected" ]]; then
+    fail "Unexpected HTTP status for ${name}: expected ${expected}, got ${code}"
+  fi
+}
+
+json_get() {
+  local file="$1"
+  local expr="$2"
+  python3 - <<PY
+import json
+from pathlib import Path
+
+payload = json.loads(Path("$file").read_text())
+value = payload
+for part in "$expr".split("."):
+    if part.isdigit():
+        value = value[int(part)]
+    else:
+        value = value[part]
+print(value if value is not None else "")
+PY
+}
+
+assert_json_value() {
+  local file="$1"
+  local expr="$2"
+  local expected="$3"
+  local actual
+  actual="$(json_get "$file" "$expr")"
+  if [[ "$actual" != "$expected" ]]; then
+    fail "JSON assertion failed for ${expr}: expected '${expected}', got '${actual}'"
+  fi
+  echo "[OK] ${expr}=${actual}"
+}
+
+step "health"
+curl -sS -i "${API_URL}/healthz" || fail "Health endpoint is unavailable"
+
+step "system"
+request "ping" "GET" "${API_URL}/api/v1/ping" "200"
+request "db_ping" "GET" "${API_URL}/api/v1/db/ping" "200"
+request "manifest" "GET" "${API_URL}/api/v1/manifest" "200"
+
+step "scheme current"
+request "current" "GET" "${API_URL}/api/v1/schemes/${SCHEME_ID}/current" "200"
+CURRENT_VERSION_ID="$(json_get "${WORKDIR}/current.body" "scheme_version_id")"
+CURRENT_STATUS="$(json_get "${WORKDIR}/current.body" "status")"
+echo "CURRENT_VERSION_ID=${CURRENT_VERSION_ID}"
+echo "CURRENT_STATUS=${CURRENT_STATUS}"
+
+step "editor context"
+request "editor_context" "GET" "${API_URL}/api/v1/schemes/${SCHEME_ID}/editor/context" "200"
+
+step "ensure draft"
+request "ensure_draft" "POST" "${API_URL}/api/v1/schemes/${SCHEME_ID}/draft/ensure" "200"
+DRAFT_VERSION_ID="$(json_get "${WORKDIR}/ensure_draft.body" "scheme_version_id")"
+DRAFT_CREATED="$(json_get "${WORKDIR}/ensure_draft.body" "created")"
+echo "DRAFT_VERSION_ID=${DRAFT_VERSION_ID}"
+echo "DRAFT_CREATED=${DRAFT_CREATED}"
+
+step "draft summary"
+request "draft_summary" "GET" "${API_URL}/api/v1/schemes/${SCHEME_ID}/draft/summary?expected_scheme_version_id=${DRAFT_VERSION_ID}" "200"
+assert_json_value "${WORKDIR}/draft_summary.body" "scheme_version_id" "${DRAFT_VERSION_ID}"
+assert_json_value "${WORKDIR}/draft_summary.body" "status" "draft"
+
+step "draft structure"
+request "draft_structure" "GET" "${API_URL}/api/v1/schemes/${SCHEME_ID}/draft/structure?expected_scheme_version_id=${DRAFT_VERSION_ID}" "200"
+assert_json_value "${WORKDIR}/draft_structure.body" "scheme_version_id" "${DRAFT_VERSION_ID}"
+SEAT_RECORD_ID="$(json_get "${WORKDIR}/draft_structure.body" "seats.0.seat_record_id")"
+SECTOR_RECORD_ID="$(json_get "${WORKDIR}/draft_structure.body" "sectors.0.sector_record_id")"
+GROUP_RECORD_ID="$(json_get "${WORKDIR}/draft_structure.body" "groups.0.group_record_id")"
+PRICED_SEAT_ID="$(json_get "${WORKDIR}/draft_structure.body" "seats.0.seat_id")"
+UNPRICED_SEAT_ID="$(json_get "${WORKDIR}/draft_structure.body" "seats.2.seat_id")"
+echo "SEAT_RECORD_ID=${SEAT_RECORD_ID}"
+echo "SECTOR_RECORD_ID=${SECTOR_RECORD_ID}"
+echo "GROUP_RECORD_ID=${GROUP_RECORD_ID}"
+echo "PRICED_SEAT_ID=${PRICED_SEAT_ID}"
+echo "UNPRICED_SEAT_ID=${UNPRICED_SEAT_ID}"
+
+step "draft validation"
+request "draft_validation" "GET" "${API_URL}/api/v1/schemes/${SCHEME_ID}/draft/validation?expected_scheme_version_id=${DRAFT_VERSION_ID}" "200"
+assert_json_value "${WORKDIR}/draft_validation.body" "status" "draft"
+
+step "draft compare preview"
+request "draft_compare" "GET" "${API_URL}/api/v1/schemes/${SCHEME_ID}/draft/compare-preview?expected_scheme_version_id=${DRAFT_VERSION_ID}" "200"
+
+step "stale draft conflict"
+request "draft_summary_stale" "GET" "${API_URL}/api/v1/schemes/${SCHEME_ID}/draft/summary?expected_scheme_version_id=deadbeefdeadbeefdeadbeefdeadbeef" "409"
+assert_json_value "${WORKDIR}/draft_summary_stale.body" "detail.code" "stale_draft_version"
+
+step "draft record reads"
+request "draft_seat_record" "GET" "${API_URL}/api/v1/schemes/${SCHEME_ID}/draft/seats/records/${SEAT_RECORD_ID}?expected_scheme_version_id=${DRAFT_VERSION_ID}" "200"
+request "draft_sector_record" "GET" "${API_URL}/api/v1/schemes/${SCHEME_ID}/draft/sectors/records/${SECTOR_RECORD_ID}?expected_scheme_version_id=${DRAFT_VERSION_ID}" "200"
+request "draft_group_record" "GET" "${API_URL}/api/v1/schemes/${SCHEME_ID}/draft/groups/records/${GROUP_RECORD_ID}?expected_scheme_version_id=${DRAFT_VERSION_ID}" "200"
+request "draft_unknown_record" "GET" "${API_URL}/api/v1/schemes/${SCHEME_ID}/draft/seats/records/deadbeefdeadbeefdeadbeefdeadbeef" "404"
+
+step "structure read model"
+request "current_sectors" "GET" "${API_URL}/api/v1/schemes/${SCHEME_ID}/current/sectors" "200"
+request "current_groups" "GET" "${API_URL}/api/v1/schemes/${SCHEME_ID}/current/groups" "200"
+request "current_seats" "GET" "${API_URL}/api/v1/schemes/${SCHEME_ID}/current/seats" "200"
+
+step "svg display pipeline"
+request "current_svg_meta" "GET" "${API_URL}/api/v1/schemes/${SCHEME_ID}/current/svg/display/meta" "200"
+
+step "pricing read model"
+request "pricing_bundle" "GET" "${API_URL}/api/v1/schemes/${SCHEME_ID}/pricing" "200"
+request "pricing_coverage" "GET" "${API_URL}/api/v1/schemes/${SCHEME_ID}/pricing/coverage" "200"
+request "pricing_unpriced" "GET" "${API_URL}/api/v1/schemes/${SCHEME_ID}/pricing/unpriced-seats" "200"
+request "pricing_explain_priced" "GET" "${API_URL}/api/v1/schemes/${SCHEME_ID}/pricing/explain/${PRICED_SEAT_ID}" "200"
+request "pricing_explain_unpriced" "GET" "${API_URL}/api/v1/schemes/${SCHEME_ID}/pricing/explain/${UNPRICED_SEAT_ID}" "200"
+request "pricing_diagnostics" "GET" "${API_URL}/api/v1/schemes/${SCHEME_ID}/pricing/rules/diagnostics" "200"
+request "seat_price" "GET" "${API_URL}/api/v1/schemes/${SCHEME_ID}/current/seats/${PRICED_SEAT_ID}/price" "200"
+request "test_mode_priced" "GET" "${API_URL}/api/v1/schemes/${SCHEME_ID}/test/seats/${PRICED_SEAT_ID}" "200"
+request "test_mode_unpriced" "GET" "${API_URL}/api/v1/schemes/${SCHEME_ID}/test/seats/${UNPRICED_SEAT_ID}" "200"
+
+step "typed validation errors"
+request "invalid_amount" "POST" "${API_URL}/api/v1/schemes/${SCHEME_ID}/pricing/rules?expected_scheme_version_id=${DRAFT_VERSION_ID}" "422" '{"pricing_category_id":"deadbeefdeadbeefdeadbeefdeadbeef","target_type":"seat","target_ref":"seat-x","amount":"bad","currency":"RUB"}'
+assert_json_value "${WORKDIR}/invalid_amount.body" "detail.code" "invalid_amount"
+
+request "remap_no_filters" "POST" "${API_URL}/api/v1/schemes/${SCHEME_ID}/draft/remap/preview?expected_scheme_version_id=${DRAFT_VERSION_ID}" "422" '{"seat_record_ids":null,"from_sector_id":null,"to_sector_id":"vip","from_group_id":null,"to_group_id":null}'
+assert_json_value "${WORKDIR}/remap_no_filters.body" "detail.code" "remap_filter_required"
+
+step "draft pricing snapshot"
+request "draft_snapshot" "POST" "${API_URL}/api/v1/schemes/${SCHEME_ID}/draft/pricing/snapshot?expected_scheme_version_id=${DRAFT_VERSION_ID}" "200"
+
+step "publish readiness"
+request "publish_readiness" "GET" "${API_URL}/api/v1/schemes/${SCHEME_ID}/draft/publish-readiness?expected_scheme_version_id=${DRAFT_VERSION_ID}" "200"
+
+step "publish preview"
+request "publish_preview_refresh" "GET" "${API_URL}/api/v1/schemes/${SCHEME_ID}/draft/publish-preview?refresh=true&expected_scheme_version_id=${DRAFT_VERSION_ID}" "200"
+request "publish_preview_cached" "GET" "${API_URL}/api/v1/schemes/${SCHEME_ID}/draft/publish-preview?expected_scheme_version_id=${DRAFT_VERSION_ID}" "200"
+
+step "admin ops"
+request "admin_artifacts" "GET" "${API_URL}/api/v1/admin/schemes/${SCHEME_ID}/current/artifacts" "200"
+request "admin_validation" "GET" "${API_URL}/api/v1/admin/schemes/${SCHEME_ID}/current/validation" "200"
+request "admin_preview_audit" "GET" "${API_URL}/api/v1/admin/artifacts/publish-preview/audit" "200"
+request "admin_preview_cleanup" "POST" "${API_URL}/api/v1/admin/artifacts/publish-preview/cleanup?dry_run=true" "200"
+
+step "audit trail"
+request "audit" "GET" "${API_URL}/api/v1/schemes/${SCHEME_ID}/audit" "200"
+
+step "done"
+echo "[OK] smoke regression completed successfully"