docs: backend contracts for Phases 8-10 (identity/messaging, tenant registry, content modules)

- Phase 8: Customer/ExternalIdentity/ContactChannel, VK ID OAuth 2.1/PKCE
  built first per Sprint 0.1 ("do all after vk"), then OTP, then MAX/
  Telegram bot linking, then the Notification Orchestrator + Delivery
  Conversation State Machine. Hard rule carried through: bots never touch
  financial statuses, only delivery fields via a dedicated Delivery Service.
- Phase 9: Marketplace/MarketplaceDomain/MarketplaceFeatureSet/
  MarketplaceRevision, full Hostinger DNS automation sequence (snapshot
  before change, never touch MX/SPF/DKIM/DMARC/CAA), lifecycle state
  machine that must expose its own blocker on every transition, publish
  model with orders/payments/inventory explicitly excluded from revisions.
- Phase 10: Gorbushka-class content entities (Shop/Service/Floor/
  SchemePin/RentListing/News/Lead/MallSettings), explicitly lowest
  priority and gated on Commerce Core being real first.

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

docs/backend/PHASE-10-CONTENT-MODULES-CONTRACT.md

@@ -0,0 +1,118 @@
+# Phase 10 Backend Contract — Tenant Content Modules (Gorbushka-class tenants)
+
+Companion to [PRODUCT-PLAN-v3.1-DELIVERY-PLAN.md](../PRODUCT-PLAN-v3.1-DELIVERY-PLAN.md) Phase 10 (Sprints 10.1–10.2). Covers plan §11.
+
+**Status: ready to build, lowest priority.** Only after Commerce Core (Phases 1–7) is real — the plan is explicit that this tenant type does not define the platform architecture; it is one configuration of the shared runtime, not a separate build.
+
+---
+
+## 1. Entities
+
+```ts
+interface Shop {
+  id: string;
+  marketplaceId: string;
+  shopCategoryId: string;
+  name: string;
+  floorId?: string;
+  status: 'draft' | 'published';
+}
+
+interface ShopCategory {
+  id: string;
+  marketplaceId: string;
+  title: string;
+}
+
+interface Service {
+  id: string;
+  marketplaceId: string;
+  title: string;
+  description: string;
+  status: 'draft' | 'published';
+}
+
+interface Floor {
+  id: string;
+  marketplaceId: string;
+  order: number;
+  label: string;
+}
+
+interface SchemePin {
+  id: string;
+  marketplaceId: string;
+  floorId: string;
+  shopId?: string;
+  x: number;
+  y: number;
+}
+
+interface RentListing {
+  id: string;
+  marketplaceId: string;
+  title: string;
+  areaSqm: number;
+  floorId?: string;
+  status: 'available' | 'leased';
+}
+
+interface Lead {
+  id: string;
+  marketplaceId: string;
+  rentListingId?: string;
+  contactName: string;
+  contactPhone: string;
+  message?: string;
+  createdAt: string;
+}
+
+interface NewsPromo {
+  id: string;
+  marketplaceId: string;
+  title: string;
+  body: string;
+  publishedAt?: string;
+}
+
+interface MallSettings {
+  marketplaceId: string;
+  openingHours: Record<string, string>;
+  contactInfo: Record<string, string>;
+}
+```
+
+Every entity above carries `marketplaceId`, an audit trail, and the same draft/preview/publish flow as [Phase 9's revision model](PHASE-9-TENANT-REGISTRY-DOMAINS-CONTRACT.md) §5 — not a separate content pipeline.
+
+## 2. Endpoints
+
+```
+GET/POST/PATCH/DELETE  /api/admin/v2/content/shops
+GET/POST/PATCH/DELETE  /api/admin/v2/content/shop-categories
+GET/POST/PATCH/DELETE  /api/admin/v2/content/services
+GET/POST/PATCH/DELETE  /api/admin/v2/content/floors
+GET/POST/PATCH/DELETE  /api/admin/v2/content/scheme-pins
+GET/POST/PATCH/DELETE  /api/admin/v2/content/rent-listings
+POST                   /api/admin/v2/content/rent-listings/{id}/leads
+GET/POST/PATCH/DELETE  /api/admin/v2/content/news
+PATCH                  /api/admin/v2/content/mall-settings
+```
+
+## 3. Tenant feature configuration (Gorbushka's v1 default, per plan §11.1)
+
+```json
+{
+  "cms": true, "shops": true, "services": true, "mallScheme": true,
+  "rentListings": true, "news": true, "seoMedia": true,
+  "catalog": false, "sellerPortal": false,
+  "cart": false, "checkout": false, "payments": false, "orders": false
+}
+```
+
+Commerce modules are **platform-ready but off** — the point of Phase 10 is proving this tenant can flip `catalog`/`cart`/`checkout`/etc. to `true` later via [Phase 9's `MarketplaceFeatureSet`](PHASE-9-TENANT-REGISTRY-DOMAINS-CONTRACT.md) with zero backend or storefront code changes, since the commerce core is already generic by the time Phase 10 starts.
+
+## 4. What the frontend will start doing once this ships
+
+- Mall scheme / floor / pin editor UI.
+- Rent listing + lead capture forms.
+- Confirm the existing Gorbushka frontend/archive is used as UX reference only — production data and auth route through the shared platform per ADR-0001.