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>

CHANGELOG.md

@@ -19,6 +19,16 @@ Format loosely follows [Keep a Changelog](https://keepachangelog.com/). Dates ar
 
 - `refactor: marketplace release polish` — accessibility pass (explicit `aria-label` on every previously-unlabeled filter `<select>` across the new admin modules), loading-skeleton consistency across admin list pages that previously rendered blank during the initial fetch, and consolidation of the admin dashboard card's custom loading shimmer onto the shared skeleton component.
 
+- **Storefront premium UX polish** (RC-Visual-02, RC-Premium-01, RC STORE-01) — composition fixes (shared skeleton/empty-state components, undefined theme vars), visual/interaction polish (hover/focus states, color-only-signal fixes), and cleanup across Home/Catalog/Search/Product/Compare/Wishlist/Cart/Static Pages. Full history: `docs/archive/`.
+- **Performance audit** (RC PERF-01) — initial bundle 1.47 MB → 1.12 MB (−24%), biggest win from lazy-loading en/hy i18n packs; dead `items-carousel`/primeng-only component removed.
+- **WCAG 2.1 AA accessibility audit** (RC A11Y-01) — first skip link added app-wide, dialog focus-trap fixes, keyboard-operable drag-and-drop fallbacks, contrast fixes.
+- **Release-candidate walkthrough** — 2 P0s fixed: an app-wide query-param routing bug, and Backoffice Categories CRUD being completely broken end-to-end.
+- **Dead-code cleanup** — removed unregistered auth guards/interceptor, unused search-analytics service, empty backoffice scaffold directories, orphaned shared barrels/models.
+
+### Please note
+
+Orders, transactions, users/roles, monitoring, and analytics run on realistic sample data for now — the backend endpoints for these don't exist yet (tracked in `docs/BACKEND_API.md`). Categories are fully wired to a real HTTP gateway; products and media remain local-storage-backed, ready for a real API to be plugged in behind the same interfaces.
+
 ### Known gaps
 
-Every feature above that reads "mock/local" or "seeded" has no real backend yet — see `docs/BACKEND.md` for the full punch list (categories, products, media, orders, transactions, users/roles, and monitoring/analytics all need real endpoints before they reflect production data). `docs/ADMIN.md` documents the architecture and trade-off decisions for each module in detail.
+Every feature above that reads "mock/local" or "seeded" has no real backend yet — see `docs/BACKEND_API_REMAINING_WORK.md` for the full punch list (products, media, orders, transactions, users/roles, and monitoring/analytics all need real endpoints before they reflect production data; categories are already wired end-to-end). `docs/ADMIN.md` documents the architecture and trade-off decisions for each module in detail. Full current status: `docs/PROJECT_INDEX.md`, `docs/FRONTEND-ROADMAP.md`, `docs/KNOWN-ISSUES.md`.