Add full system audit reports and Telegram Mini App debug handoff

- Three-stream audit (security / logic / performance) with 35+ findings
  derived from actual source code, each with file:line and remediation
- Audit Index cross-references criticals across streams into prioritized
  fix tiers: immediately / before soft launch / before public launch
- Telegram Mini App debug handoff documenting what was implemented and
  all remaining work items with exact file lists and test commands
- Updated architecture, data model, auth API, and registration flow docs
  to reflect Telegram auth, TON wallet, and email verification additions

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

02 - Data Models/Data Model Overview.md

@@ -9,7 +9,7 @@ aliases: [Models Index, Schema Overview]
 This section documents every Mongoose model that backs the marketplace. The persistence layer lives in `backend/src/models/` and is exported through a single barrel file at `backend/src/models/index.ts`. All models target MongoDB via Mongoose, lean on `timestamps: true` for `createdAt` / `updatedAt`, and follow a consistent pattern: one schema per file, an exported `I<Name>` TypeScript interface, and named exports for the compiled model.
 
 > [!note] Scope
-> Sixteen models are documented here. The "File" concept exists only at the service layer (`backend/src/services/file/`) and is not persisted as its own Mongoose collection, so it is not listed below.
+> Eighteen models are documented here. The "File" concept exists only at the service layer (`backend/src/services/file/`) and is not persisted as its own Mongoose collection, so it is not listed below.
 >
 > [!warning] Implementation gap
 > As of the 2026-05-24 audit, the following documented models **do not yet have Mongoose schema files** in `backend/src/models/`:
@@ -20,7 +20,7 @@ This section documents every Mongoose model that backs the marketplace. The pers
 > - [[LevelConfig]]
 > - [[ShopSettings]]
 > The following *are* implemented in code and are documented accurately:
-> - [[User]], [[PurchaseRequest]], [[SellerOffer]], [[Payment]], [[Chat]], [[Notification]], [[RequestTemplate]], [[Address]], [[Category]], [[TempVerification]]
+> - [[User]], [[PurchaseRequest]], [[SellerOffer]], [[Payment]], [[Chat]], [[Notification]], [[RequestTemplate]], [[Address]], [[Category]], [[TempVerification]], [[TelegramLink]], [[TelegramSession]]
 > Additionally, `FundsLedgerEntry.ts` and `TrezorAccount.ts` exist in `backend/src/models/` but are not yet documented in this vault.
 
 ## Index of Models
@@ -41,6 +41,8 @@ This section documents every Mongoose model that backs the marketplace. The pers
 - [[LevelConfig]] — Static configuration of loyalty tiers (level number, point thresholds, benefits, icon, color). Driven by admins; consumed by the [[User]].points.level field.
 - [[ShopSettings]] — One-to-one storefront branding for a seller: name, description, avatar, cover image, review toggles, and social links.
 - [[TempVerification]] — Short-lived signup record that holds candidate user data and a verification code. Auto-purges via TTL when `emailVerificationCodeExpires` passes.
+- [[TelegramLink]] — Permanent auditable association between a Telegram user ID and an Amanat [[User]]. Stores Telegram profile metadata, link source (`miniapp` / `bot` / `login_widget`), status (`active` / `blocked`), and last-seen timestamp. One per Telegram user (unique on both `userId` and `telegramUserId`).
+- [[TelegramSession]] — Short-lived Telegram Mini App session token issued when `initData` is verified. Carries the `initDataFingerprint` for replay protection and auto-expires via a MongoDB TTL index on `expiresAt`.
 
 ## Relationship Diagram
 
@@ -83,6 +85,10 @@ erDiagram
     LEVEL_CONFIG ||..|| USER : "level lookup"
 
     TEMP_VERIFICATION ||..|| USER : "promoted to"
+
+    TELEGRAM_LINK }o--|| USER : "links identity"
+    TELEGRAM_SESSION }o--o| USER : "session for"
+    TELEGRAM_SESSION }o--|| TELEGRAM_LINK : "matches"
 ```
 
 ## Conventions Across All Models