feat(ws2): ADR-093 路由統一 — BIGINT + NotificationMatrix + feature flag

## 修復

### T2.1 BigInteger overflow 修復
- `db/models.py`: telegram_chat_id Integer → BigInteger
  （原 int32 無法容納群組 ID -1003711974679）

### T2.2 移除 CAST workaround
- `approval_db.py:739`: 移除 CAST(:telegram_chat_id AS BIGINT)
  ORM 已正確使用 BigInteger，workaround 可退役

### T2.3 Redis key 一致性修復
- `heartbeat_report_service.py:575`: telegram:polling_leader → telegram:polling:leader
  （telegram_gateway.py 使用冒號分隔，heartbeat 用底線是 bug）

## 新增

### T2.4 notification_matrix.py
- `services/notification_matrix.py`: ADR-093 路由矩陣
  - Destination(DM/GROUP/BOTH) + RoutingRule dataclass
  - NOTIFICATION_ROUTING dict（TYPE-1 ~ TYPE-8M 完整映射）
  - resolve_chat_ids(type, dm, group, *, tg_group_cutover=False) 灰階切流 API

### T2.5 telegram_gateway.py feature flag 保護
- line 43: 加 notification_matrix import
- line 1827-1834: TG_GROUP_CUTOVER=False 時維持舊行為
  TG_GROUP_CUTOVER=True 時解除 _interactive_types 黑名單，由矩陣控制

### T2.6 Migration SQL
- `migrations/adr093_notification_routing.sql`:
  - CREATE TABLE approval_records (telegram_chat_id BIGINT)
  - CREATE ROLE awoooi_migrator (IF NOT EXISTS)
  - 含舊環境 ALTER COLUMN int→bigint 保護

## 測試同步
- `tests/integration/setup_test_schema.sql`: telegram_chat_id BIGINT

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

apps/api/src/services/telegram_gateway.py

@@ -40,6 +40,7 @@ from src.services.security_interceptor import (
     get_security_interceptor,
 )
 from src.services.chat_manager import get_chat_manager
+from src.services.notification_matrix import resolve_chat_ids  # ADR-093 路由矩陣
 
 # =============================================================================
 # Snooze/Silence Redis Keys (2026-03-27 P1 優化)
@@ -1823,11 +1824,14 @@ class TelegramGateway:
         # 2026-04-12 ogt: ADR-075 斷點 C 修復 — 含按鈕的互動型通知禁止發群組（nonce 洩漏）
         #   TYPE-1/TYPE-2 → 可發群組（純資訊，無 callback 按鈕）
         #   TYPE-3/TYPE-4/TYPE-4D/TYPE-8M → 僅 DM，不發群組
+        # ADR-093 灰階切流：TG_GROUP_CUTOVER=true 時解除 _interactive_types 黑名單
+        # 改由 notification_matrix.resolve_chat_ids() 控制路由
         _interactive_types = {"TYPE-3", "TYPE-4", "TYPE-4D", "TYPE-8M"}
         _is_interactive = notification_type in _interactive_types or (
             not notification_type and alert_category  # 有分類但無明確型別 → 視為互動型
         )
-        if settings.SRE_GROUP_CHAT_ID and not _is_interactive:
+        _cutover = getattr(settings, "TG_GROUP_CUTOVER", False)
+        if settings.SRE_GROUP_CHAT_ID and (not _is_interactive or _cutover):
             asyncio.create_task(
                 self._send_approval_card_to_group(
                     approval_id=approval_id,