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-9-Product-Engagement-Report.md

@@ -0,0 +1,112 @@
+# Sprint 9 - Product Engagement Report
+
+## 1. Architecture Decisions
+- Product engagement was implemented as a dedicated module under product feature: `src/app/features/website/product/engagement/components`.
+- ProductFacade remained the single feature entry point for engagement flows:
+  - `loadRating(productID)`
+  - `loadReviews(productID, query)`
+  - `loadQuestions(productID, query)`
+  - `submitReview(productID, input)`
+  - `submitQuestion(productID, input)`
+- No feature component uses `HttpClient` directly.
+- Data flow remains layered:
+  - Feature Container/Components -> `ProductFacade` -> `ProductDataService` -> `ProductDataProvider` (`ApiProductDataProvider`) -> `ApiService`.
+- Existing auth/payment/bootstrap initialization flows were not changed.
+- Widget/section/bootstrap runtime architecture was preserved.
+
+## 2. Reusable Components Added
+### Product Engagement Atoms
+- `StarsComponent`
+- `StarSelectorComponent`
+- `ProductTabsComponent`
+- `RatingSummaryComponent`
+
+### Reviews
+- `ReviewFormComponent`
+- `ReviewCardComponent`
+- `ReviewListComponent` (includes pagination support)
+
+### Questions
+- `QuestionFormComponent`
+- `QuestionCardComponent`
+- `QuestionListComponent` (includes pagination + Ask Question toggle)
+
+### Product Page Sections
+- Existing reusable sections kept:
+  - Gallery, Product Info, Variant Selector, Delivery, Description, Related Products
+- New/updated reusable sections:
+  - `ProductSpecificationsComponent`
+  - `ProductWarrantyComponent`
+  - Reviews section via `ReviewListComponent`
+  - Questions section via `QuestionListComponent`
+
+## 3. Domain Models Added
+File: `src/app/core/products/models/product-engagement.model.ts`
+- `RatingSummary`
+- `Review`
+- `Question`
+- `Answer`
+- Supporting contracts:
+  - `RatingDistributionEntry`
+  - `EngagementListQuery`
+  - `EngagementListResult<T>`
+  - `SubmitReviewInput`
+  - `SubmitQuestionInput`
+
+## 4. Bootstrap Additions (Feature Config Only)
+Added new optional config model:
+- `src/app/shared/models/config/product-page-config.model.ts`
+
+Added to bootstrap contract:
+- `BootstrapConfig.productPage?: ProductPageConfig`
+
+Added to mock bootstrap example:
+- `src/assets/mock/bootstrap/bootstrap.json` now contains `productPage` with:
+  - `rating.enabled`
+  - `reviews.enabled/pageSize/showSummary`
+  - `questions.enabled/pageSize`
+  - `tabs.enabled/items`
+  - `relatedProducts.enabled`
+
+No review/question domain data was placed in bootstrap.
+
+## 5. Backend Endpoints Expected
+Prepared in docs/contracts as target backend API:
+- `GET /products/{id}/rating`
+- `GET /products/{id}/reviews`
+- `GET /products/{id}/questions`
+- `POST /products/{id}/reviews`
+- `POST /products/{id}/questions`
+
+Current runtime uses existing available mock/API item data mapping where applicable, while facade methods and contracts are already prepared for dedicated engagement endpoints.
+
+## 6. Validation Results
+### Build
+- `npm run build` -> PASS
+
+### Architecture Rules
+- No `HttpClient` usage found in feature layer (`src/app/features/**`).
+- No `environment.*` usage found in feature layer (`src/app/features/**`).
+- No DTO imports found in feature layer (`src/app/features/**`, checked for `\bdto\b|\.dto`).
+
+### Architecture Governance Scripts
+- `npm run arch:check:boundaries` -> PASS
+- `npm run arch:check:cycles` -> PASS (`No circular dependency found`)
+
+## 7. Documentation Updated
+Platform docs:
+- `docs/platform/00-bootstrap-example.md`
+- `docs/platform/02-bootstrap-json-spec.md`
+- `docs/platform/06-api-contracts.md`
+- `docs/platform/10-product-domain.md`
+- `docs/platform/13-backend-requirements.md`
+
+Backend docs:
+- `docs/backend-platform/business-apis.md`
+
+## 8. Future Extension Points
+- Photo upload support in review form (placeholder is already present in UI).
+- Backend-side moderation and verification flags for reviews/questions.
+- Dedicated seller identity and accepted-answer workflow integration.
+- Server-driven sorting/filtering for reviews and questions.
+- Optional widgetized engagement blocks for dynamic page composition.