docs: replace 62 scattered/stale markdown files with two living references

Removes all tracked repo documentation (root status docs, docs/,
docs/architecture/foundation/**, docs/archive/**, docs/context/BACKEND-AUDIT.md
+ adrs, src/assets/mock/README.md) and replaces it with:

- GAPS-AND-IMPROVEMENTS.md — role-based findings (user, PO, QA, backend,
  accessibility, engineering) plus automated code-review passes over the
  storefront and backoffice, each with file:line references. Findings only,
  no fixes applied.
- BACKEND-API-REFERENCE.md — single consolidated backend contract: auth
  (both mechanisms), bootstrap, pagination/sorting/filtering conventions,
  error model, every live/mock-only endpoint with JSON examples, and the
  admin-domain DI-token seam gaps.

Open items and unresolved decisions from the deleted docs (KNOWN-ISSUES,
PRODUCT_BACKLOG, SPRINT-PLAN-NEXT, Seller-Management audits, etc.) were
harvested into the two new files before deletion, not lost.

CLAUDE.md/AGENTS.md/GEMINI.md/.claude/ and docs/context/{INDEX,LOG,
MAINTENANCE,README}.md are untouched — confirmed gitignored, never part of
git history, outside this cleanup's scope.

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

CHANGELOG.md

@@ -1,34 +0,0 @@
-# Changelog
-
-Format loosely follows [Keep a Changelog](https://keepachangelog.com/). Dates are commit dates on the `B2B` branch.
-
-## [Unreleased]
-
-### Added
-
-- **Category management** (`feat(admin): complete category management`) — full admin CRUD for categories: hierarchy (parent/child), drag-and-drop reorder, visibility toggle, item counter, empty-category handling, soft delete + restore, draft/publish workflow with local draft recovery, unsaved-changes guard, slug validation, translations, SEO fields, breadcrumb preview, category image via the shared media picker.
-- **Product management completion** (`feat(admin): complete product management`) — archive/restore, barcode field, lightweight variants, related-products picker, gallery via the shared media picker, discounted-price preview, infinite-scroll list mode; products now source their category list from the new category management module instead of a separate mock.
-- **Media system hardening** (`feat(media): reusable media management`) — folder tagging, tag editing, upload validation (size/type), SVG sanitization (script/event-handler stripping), automatic image compression/resize on upload; the shared media picker is now wired into category images, product gallery, and Project Editor branding (logo/compact logo/favicon).
-- **Order management** (`feat(admin): order management`) — new admin module: order list (search/status/pagination/CSV export) and detail view (customer/payment/shipping, itemized total, status timeline, change-status, refund request, cancel, customer + internal notes, print invoice). Seeded with synthetic mock orders — no backend order domain exists yet.
-- **Transaction management** (`feat(admin): transaction management`) — payments/refunds/QR transaction list derived from the mock order data, with status/type filters, retry-failed, fraud flagging, per-transaction audit log, CSV export.
-- **Users & permissions** (`feat(admin): users and permissions`) — new admin module: users (marketplace vs office admin scope), 4 built-in roles, invitations, per-user mock session list with revoke, per-user audit log. Confirms passwordless (Telegram QR) admin login was already real and links to it rather than reimplementing.
-- **Monitoring center** (`feat(admin): monitoring center`) — unified audit/security/login/failed-login/API/error/warning event feed, mock queue and webhook-delivery views, and a Health section that reuses the existing real dashboard health checks.
-- **Analytics dashboard** (`feat(admin): analytics dashboard`) — revenue/orders/average-order-value/top-products computed from the mock order data, product/category counts from their respective modules, a sales-over-time bar chart with 7/30/90-day ranges, CSV export. Visitor/funnel/heatmap sections show an explicit "awaiting backend integration" state rather than fabricated numbers, since no analytics pipeline exists.
-
-### Changed
-
-- `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_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`.