chore: 迁移到 social-app 架构，集成 Supabase 和 taskiq worker

backend/AGENTS.md

@@ -49,6 +49,32 @@ This file governs `backend/**` only. Keep it minimal, enforceable, and non-dupli
 - Strong typing required at boundaries (Pydantic/dataclass); avoid weak untyped payload contracts.
 - Protocol/data contract changes must stay aligned with `docs/protocols/`.
 
+## Database Rules
+
+- Supabase Auth is identity source; backend enforces business authorization.
+- Use service-role DB access only in backend.
+- Soft delete uses `deleted_at`; reads must exclude deleted records by default.
+- Alembic is the only schema migration source of truth.
+- Database migrations use `./infra/scripts/dev-migrate.sh`:
+  - `migrate` - run migrations only
+  - `init-data` - seed data only
+  - `bootstrap` - migrate + init-data
+
+## Agent Runtime & Tools
+
+- AG-UI protocol is mandatory for agent loop behavior.
+- `ToolAgentOutput.result` is the canonical tool result field.
+- Tool results must be machine-oriented and include IDs/outcomes needed for chaining.
+
+## Tool Schema Rules for Small Models (e.g., qwen3.5-flash)
+
+- Prefer `operations: list[OperationModel]` over parallel arrays.
+- Validate tool args with strict Pydantic models (`extra="forbid"`).
+- Keep payloads JSON-native (objects/lists), shallow, and deterministic.
+- Make action-specific required fields explicit and fail with structured errors.
+- Return per-item outcomes (`success/failed`, identifiers, partial status) for self-correction.
+- Avoid broad entry-point coercion fallbacks; fix schema/prompt alignment first.
+- Do not pass provider request fields with `None` values (avoid upstream 400 blocking tool calls).
 
 ## Testing