docs: complete code-reality alignment for remaining docs + reconcile issue set

Remaining docs updated to match code (the docs that the first pass had not covered):
- Flows: Chat, Referral, Rating, Registration, Google OAuth, Negotiation, Payout,
  Trezor Safekeeping — corrected endpoints, socket events, status enums, auth gaps
- API Reference: User API, Trezor API — admin route prefix/verb/status corrections,
  added undocumented endpoints (ton-proof challenge, profile email verify,
  GET /trezor/account, POST /trezor/verify-operation)
- Data Models: Chat, Notification, Payment, PointTransaction, User — corrected
  enums (PaymentProvider, escrowState, PointTransaction.type, User.status),
  90-day notification TTL, soft-delete semantics, wallet fields

Trezor "zero frontend" finding (audit C31/C32) corrected as STALE:
- Verified current code HAS a full frontend Trezor implementation (admin/trezor
  page, TrezorSettingsView, trezorConnector via @trezor/connect-web,
  TrezorSignDialog, actions/trezor.ts building the {message,signature} object)
- Fixed Trezor Safekeeping Flow doc (removed false "no frontend" warnings)
- Reclassified ISSUE-012 as invalid/superseded with explanation

Issue set reconciled to a single canonical numbering (ISSUE-001..054):
- Adopted the comprehensive 51-issue set (long-slug, fully indexed)
- Removed 35 superseded short-slug duplicates from the first pass
- Removed a duplicate ISSUE-046 file
- Added 3 issues the 51-set lacked: ISSUE-052 (completed-not-counted-in-stats),
  ISSUE-053 (axios 401-only interceptor), ISSUE-054 (rate limiter counts all attempts)
- Regenerated Issues Index: 53 open (14 critical, 39 major) + 1 invalid

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

04 - Flows/Purchase Request Flow.md

@@ -5,6 +5,8 @@ related_models: ["[[PurchaseRequest]]", "[[Category]]", "[[Address]]", "[[Seller
 related_apis: ["POST /api/marketplace/purchase-requests", "GET /api/marketplace/purchase-requests", "PATCH /api/marketplace/purchase-requests/:id"]
 ---
 
+> **Last updated:** 2026-05-29 — aligned with code (see Doc vs Code Audit Report)
+
 > [!warning] Audit — 2026-05-29
 > This document was corrected against the live codebase. Key changes: status enum updated (added `pending_payment`, `active`; removed undocumented `finalized`/`archived`); urgency values expanded to include `urgent`; sellers endpoint corrected; attachment upload endpoint corrected; `request-cancelled` socket event removed (non-existent); `new-purchase-request` fan-out target corrected to shared `sellers` room; socket room join/leave events documented; description minimum corrected to 5 chars; PUT vs PATCH mismatch flagged as known bug; two frontend actions hitting non-existent backend endpoints flagged as not implemented.