docs: consolidate documentation and archive temporary reports

Step 1-2 (audit + plan): classified 35 project markdown files into
Core/Architecture/ADR/Temporary-audit/Sprint-report/Generated-review/
Duplicate/Obsolete/Historical. Agent-tooling files (.agents/skills/**,
.superpowers/**, docs/context/**, CLAUDE.md/GEMINI.md/AGENTS.md/
.github/copilot-instructions.md) explicitly out of scope — intentional
per-tool duplication, not documentation debt.

Step 3 (merge, no information lost):
- docs/PROJECT.md -> docs/PROJECT_INDEX.md, rewritten as the single
  entry point: system overview, living-doc index, archive pointer,
  current status, and a critical-finding callout up top.
- docs/backend/BACKEND-INTEGRATION.md -> docs/BACKEND_API.md,
  docs/backend/REMAINING-BACKEND-WORK.md ->
  docs/BACKEND_API_REMAINING_WORK.md (also folded in a legitimate
  uncommitted status update that had been sitting unstaged all
  session: categories marked DONE, order-creation endpoint noted done).
- RELEASE-NOTES.md merged into CHANGELOG.md (was a near-duplicate of
  the same release content in friendlier prose), then deleted.
- KNOWN-ISSUES.md: added item 13 (see below) and item 14 (missing
  canDeactivate on admin/products edit, from the archived PROJECT-STATE
  audit, re-verified still true); added a correction note to Fixed
  item 7.
- All cross-references to renamed/moved files fixed across every
  kept doc (grep+sed pass, then verified with a link-existence check
  across all 58 in-scope markdown files -> 0 broken links).

Step 4 (archive, nothing deleted without merging first): created
docs/archive/, moved 19 files there (3 root sprint reports, 1 platform
report, SPRINT-PLAN.md, and 14 one-off audit/review/report docs).
Added correction headers to the 3 archived docs whose conclusions were
affected by the finding below, rather than silently leaving them
misleading.

Step 5: docs/PROJECT_INDEX.md rewritten per the mission brief -
someone opening the repo should understand the whole system from it.

IMPORTANT FINDING (surfaced during this audit, not the mission's
primary goal but too significant to bury): pages/category/*,
pages/search/*, pages/item-detail/*, pages/info/**, pages/legal/**
(40+ files) are entirely unrouted dead code - app.routes.ts's
cmsContentRoutes is a literal empty array, and category/search/product
routes redirect to CatalogContainerComponent/
ProductDetailsContainerComponent, not these files. Confirmed against
app.routes.ts directly and cross-checked against FRONTEND.md's own
routing description. This means several fixes from earlier this cycle
(RC-Premium-01, RC STORE-01) and the dead-code cleanup sprint's
conclusion that these files were live were all wrong - documented as
KNOWN-ISSUES.md item 13, flagged at the top of PROJECT_INDEX.md, and
noted on the 3 archived docs whose conclusions it affects. No
application code was changed to fix this (out of scope per this
session's 'documentation only' constraint) - it needs a wire-it-up-or-
delete-it decision first.

Verification: tsc --noEmit clean, npm run build green, all markdown
links across 58 in-scope files resolve (checked programmatically).
No application/Angular/backend code modified.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

docs/archive/Sprint-10-Advanced-Search-Report.md

@@ -0,0 +1,133 @@
+# Sprint 10 - Advanced Search & Catalog Report
+
+## 1. Architecture
+- Existing platform architecture was preserved.
+- No authentication flow changes.
+- No payment flow changes.
+- No bootstrap loading flow changes.
+- Widget engine and section engine were not modified.
+- ProductFacade was only extended (no contract removals or breaking changes).
+
+### Data Flow
+- Catalog UI calls ProductFacade only.
+- ProductFacade extensions for sprint 10:
+  - search(criteria)
+  - filter(criteria)
+  - sort(criteria)
+  - loadCatalog(criteria)
+- No HttpClient usage in feature layer.
+
+## 2. New Reusable Components
+### Search Module
+- CatalogSearchBoxComponent
+  - keyword search
+  - instant suggestions (frontend-prepared, backend-ready)
+  - recent searches
+  - search history
+  - loading and no-results hint
+
+### Filters Module
+- CatalogFiltersPanelComponent
+  - dynamic filter rendering from filter definitions
+  - supports multi-select, range, toggle filter types
+
+### Sorting Module
+- CatalogSortingControlComponent
+  - configurable sort options
+
+### Layout Module
+- CatalogLayoutSwitcherComponent
+  - grid
+  - large grid
+  - compact grid
+  - list
+
+### Search Results Module
+- CatalogSearchResultsComponent
+  - loading skeletons
+  - summary
+  - pagination
+  - empty state
+
+### Product Card Enhancements
+- Added placeholders (no business logic):
+  - favorite
+  - compare
+  - quick view
+- Added stock badge and configurable discount/rating/availability visibility.
+
+## 3. Domain Models
+Added reusable catalog/search models:
+- SearchCriteria
+- FilterDefinition
+- FilterOption
+- SortDefinition
+- CatalogView
+- SearchResult
+
+File:
+- src/app/core/products/models/catalog-experience.model.ts
+
+## 4. Bootstrap Additions
+Added catalog feature configuration (config only, no catalog data):
+- layout
+- navigationMode
+- defaultSort
+- availableSorts
+- enabledFilters
+- showBreadcrumbs
+- showCategoryBanner
+- showSubcategoryChips
+- showRatings
+- showDiscounts
+- showAvailability
+- suggestionsEnabled
+- searchHistoryEnabled
+
+Files:
+- src/app/shared/models/config/catalog-config.model.ts
+- src/app/shared/models/config/bootstrap-config.model.ts
+- src/assets/mock/bootstrap/bootstrap.json
+
+## 5. Backend Expectations
+Documented current and future-ready expectations:
+- Current:
+  - GET /searchitems
+  - GET /category/{id}
+- Future-ready:
+  - GET /search/suggestions?q={term}
+  - GET /catalog/filters?category={id}&q={term}
+
+## 6. Validation Results
+### Build
+- npm run build: PASS
+
+### Architecture
+- npm run arch:check:boundaries: PASS
+- npm run arch:check:cycles: PASS
+
+### Layering checks
+- HttpClient in feature layer: none found
+- DTO leaks in feature layer: none found (search matched addToCart text only, not DTO usage)
+
+### Compatibility
+- Widget compatibility preserved
+- Section engine compatibility preserved
+
+## 7. Documentation Updated
+- docs/platform/00-bootstrap-example.md
+- docs/platform/02-bootstrap-json-spec.md
+- docs/platform/06-api-contracts.md
+- docs/platform/08-catalog-domain.md
+- docs/platform/13-backend-requirements.md
+- docs/backend-platform/business-apis.md
+
+## 8. Future Extension Points
+- Backend-driven suggestions endpoint integration.
+- Backend-driven dynamic filter metadata (option counts/ranges/facets).
+- Navigation mode implementations:
+  - left category navigation
+  - mega category layout
+  - top category carousel
+- URL-state sync for all search/filter/sort/layout inputs.
+- Dedicated saved searches / personalized search suggestions.