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/KNOWN-ISSUES.md

@@ -38,7 +38,7 @@ don't fix inline unless asked.
    - Found: 2026-07-15, during Sprint 28 manual audit (reading templates +
      grepping i18n files, not live browser).
    - **Deferred to Sprint 29** ("translation validation" is explicit Sprint 29
-     scope per `docs/SPRINT-PLAN.md`) rather than fixed inline during Sprint
+     scope per `docs/archive/SPRINT-PLAN.md`) rather than fixed inline during Sprint
      28 polish - authoring ~534 correct strings across 3 languages is a large,
      separate, mechanical pass of its own and shouldn't be rushed inside a
      polish sprint. Sprint 28 only adds the handful of new keys it introduces
@@ -80,11 +80,11 @@ don't fix inline unless asked.
    Correction (2026-07-24, RC A11Y-01): the "already has focus-trap" assumption
    below was wrong — it had none. RC A11Y-01 ported `app-dialog`'s confirmed-
    correct focus-trap/Escape/return-focus pattern directly onto it
-   (`docs/ACCESSIBILITY_REPORT.md`), so the accessibility gap is closed. It's
+   (`docs/archive/ACCESSIBILITY_REPORT.md`), so the accessibility gap is closed. It's
    still a separate custom component, not the shared `app-dialog` itself —
    migrating it to the actual primitive remains a composition change,
    deliberately left out of every polish pass so far.
-   - Found: 2026-07-23, RC-Premium-01 (`docs/STORE_FRONT_UX_REVIEW.md`).
+   - Found: 2026-07-23, RC-Premium-01 (`docs/archive/STORE_FRONT_UX_REVIEW.md`).
 
 7. **Cart's `clearCart()` uses native `confirm()`, no styled confirm dialog.**
    No existing storefront pattern for a confirm-remove dialog to follow yet —
@@ -102,13 +102,13 @@ don't fix inline unless asked.
    `--success/--warning/--error/--info-color` fail 4.5:1 when used as plain
    text-on-white in a handful of places. Real palette colors, not a token
    bug — fixing means visibly changing the brand, needs theme-owner sign-off.
-   - Found: 2026-07-24, RC A11Y-01 (`docs/ACCESSIBILITY_REPORT.md`).
+   - Found: 2026-07-24, RC A11Y-01 (`docs/archive/ACCESSIBILITY_REPORT.md`).
 
 10. **Footer "Contacts" link has no static-page content in mock data.**
     Unlike the "About" link (which was a route-name mismatch, fixed), no
     content exists for Contacts at all — needs a content decision, not a
     code fix.
-    - Found: 2026-07-24, Release Candidate walkthrough (`docs/RELEASE_REPORT.md`).
+    - Found: 2026-07-24, Release Candidate walkthrough (`docs/archive/RELEASE_REPORT.md`).
 
 11. **Builder's static-page body editor is hidden and mislabeled.** The
     actual WYSIWYG content editor isn't on the "Content" tab (title/image
@@ -123,7 +123,46 @@ don't fix inline unless asked.
     pre-existing, unrelated broken `barry-cache` devDependency resolution —
     fix that first, then drop the now-fully-unused dependency (likely closes
     most of the remaining bundle-budget overage in one move).
-    - Found: 2026-07-24, RC PERF-01 (`docs/PERFORMANCE_REPORT.md`).
+    - Found: 2026-07-24, RC PERF-01 (`docs/archive/PERFORMANCE_REPORT.md`).
+
+13. **CRITICAL — `pages/category/*`, `pages/search/*`, `pages/item-detail/*`,
+    `pages/info/**`, `pages/legal/**` (40+ files) are entirely unrouted dead
+    code, not live pages.** Verified directly against `src/app/app.routes.ts`:
+    `category/:id` and `category/:id/items` `redirectTo: 'catalog/:id'`
+    (served by `CatalogContainerComponent`); `search` also routes to
+    `CatalogContainerComponent`; `product/:id` routes to
+    `ProductDetailsContainerComponent`, not `pages/item-detail`;
+    `cmsContentRoutes` (meant to route `pages/info/**`/`pages/legal/**`) is a
+    literal empty array (`app.routes.ts:292`) behind a
+    `// TODO(CMS): Resolve informational/legal pages from backend content
+    configuration here` comment — About/Contacts/FAQ/Delivery/Guarantee/
+    Company-Details/Payment-Terms/Return-Policy/Public-Offer/Privacy-Policy
+    are all actually served by the catch-all `:staticPath` route resolving
+    `bootstrap.staticPages` (`pages/static-page/static-page.component.ts`),
+    confirmed independently by `docs/FRONTEND.md`'s own routing section
+    ("Static/CMS pages resolve dynamically... no hardcoded page list").
+    **This means several "fixes" earlier in this document and in
+    `docs/archive/` were applied to dead code with zero production effect**
+    — see the correction note on Fixed item 7 below. This was missed by
+    three separate passes this cycle (RC-Premium-01, RC STORE-01, and the
+    dead-code cleanup sprint, which manually re-verified against
+    `app.routes.ts` and still concluded these files were live — an error in
+    that verification, not a tooling blind spot this time) before being
+    caught during the documentation-consolidation pass. Needs a decision:
+    wire `cmsContentRoutes` back up (restoring 10 hardcoded per-locale pages
+    that duplicate what the CMS static-page renderer already does), or
+    delete all 40+ files as genuinely dead now that the duplication is
+    confirmed intentional-by-omission rather than accidental.
+    - Found: 2026-07-25, Documentation Cleanup pass.
+
+14. **No `canDeactivate` guard on `admin/products/:id/edit`.** Categories
+    protect against navigating away with unsaved changes
+    (`adminCategoryDirtyGuard`, `app.routes.ts:121,131`); products do not,
+    despite `AdminProductsFacade` having its own dirty-tracking draft logic.
+    Inconsistent, low-effort fix (mirror the categories guard) but not
+    applied here — this pass is documentation-only.
+    - Found: 2026-07-19 (`docs/archive/PROJECT-STATE.md`), re-verified
+      2026-07-25 against current `app.routes.ts` — still true.
 
 ## Fixed
 
@@ -280,7 +319,11 @@ don't fix inline unless asked.
    `.skeleton-card`/`.skeleton-image`/`.skeleton-line` shimmer CSS with
    hardcoded hex colors, duplicating what `app-skeleton` already provides
    and what `catalog-container`/`product-details-container` already use.
-   - Fixed: 2026-07-23, RC STORE-01 (`docs/STORE_REVIEW.md`).
+   - Fixed: 2026-07-23, RC STORE-01 (`docs/archive/STORE_REVIEW.md`).
+   - **Correction (2026-07-25):** these files are unrouted dead code (Open
+     item 13) — the fix is real and harmless but currently has zero
+     production effect. Live category/search rendering goes through
+     `CatalogContainerComponent`, not these files.
 
 8. **Cart's dead `.email-form` markup and CSS removed.** Post-payment
    email/phone-capture form was commented-out markup with a matching
@@ -295,7 +338,7 @@ don't fix inline unless asked.
    a dead route). This guard runs on every top-level route app-wide, so any
    bookmarked/shared deep link with query params was silently broken —
    found during the Builder RC walkthrough but affects all 3 surfaces.
-   - Fixed: 2026-07-24, Release Candidate walkthrough (`docs/RELEASE_REPORT.md`),
+   - Fixed: 2026-07-24, Release Candidate walkthrough (`docs/archive/RELEASE_REPORT.md`),
      `router.parseUrl()` instead of a hand-built path segment.
 
 10. **Backoffice Categories CRUD completely broken end-to-end (P0).**