feat(backend): add operational smoke tooling and safe pricing cleanup endpoints

- add backend README and refresh API map and smoke regression docs
- add full backend smoke regression script
- add admin pricing cleanup preview and dry-run endpoints
- add helper script for test pricing cleanup
- verify typed error contracts, draft flow, publish readiness and preview flows
- verify publish preview retention and clean backend startup behavior

backend/app/api/routes/__init__.py

@@ -1,6 +1,7 @@
 from fastapi import APIRouter
 
 from app.api.routes.admin import router as admin_router
+from app.api.routes.admin_cleanup import router as admin_cleanup_router
 from app.api.routes.audit import router as audit_router
 from app.api.routes.editor import router as editor_router
 from app.api.routes.pricing import router as pricing_router
@@ -22,5 +23,6 @@ router.include_router(pricing_diagnostics_router)
 router.include_router(test_mode_router)
 router.include_router(audit_router)
 router.include_router(admin_router)
+router.include_router(admin_cleanup_router)
 router.include_router(editor_router)
 router.include_router(publish_router)

backend/app/api/routes/admin_cleanup.py

@@ -0,0 +1,55 @@
+from fastapi import APIRouter, Depends, Query
+
+from app.core.config import settings
+from app.schemas.admin_cleanup import (
+    PricingCleanupExecuteRequest,
+    PricingCleanupExecuteResponse,
+    PricingCleanupPreviewResponse,
+)
+from app.security.auth import require_api_key
+from app.services.pricing_cleanup import (
+    build_pricing_cleanup_preview,
+    execute_pricing_cleanup,
+)
+
+router = APIRouter()
+
+
+@router.get(
+    f"{settings.api_v1_prefix}/admin/schemes/{{scheme_id}}/pricing/categories/cleanup-preview",
+    response_model=PricingCleanupPreviewResponse,
+)
+async def get_pricing_cleanup_preview(
+    scheme_id: str,
+    code_prefix: list[str] = Query(default_factory=list),
+    name_prefix: list[str] = Query(default_factory=list),
+    pricing_category_id: list[str] = Query(default_factory=list),
+    delete_only_without_rules: bool = Query(default=True),
+    role: str = Depends(require_api_key),
+):
+    return await build_pricing_cleanup_preview(
+        scheme_id=scheme_id,
+        code_prefixes=code_prefix,
+        name_prefixes=name_prefix,
+        pricing_category_ids=pricing_category_id,
+        delete_only_without_rules=delete_only_without_rules,
+    )
+
+
+@router.post(
+    f"{settings.api_v1_prefix}/admin/schemes/{{scheme_id}}/pricing/categories/cleanup",
+    response_model=PricingCleanupExecuteResponse,
+)
+async def post_pricing_cleanup(
+    scheme_id: str,
+    payload: PricingCleanupExecuteRequest,
+    role: str = Depends(require_api_key),
+):
+    return await execute_pricing_cleanup(
+        scheme_id=scheme_id,
+        code_prefixes=payload.code_prefixes,
+        name_prefixes=payload.name_prefixes,
+        pricing_category_ids=payload.pricing_category_ids,
+        delete_only_without_rules=payload.delete_only_without_rules,
+        dry_run=payload.dry_run,
+    )