feat(ai): Phase 24-A+B1 — AI Provider Registry + 絞殺者包裝 (ADR-052)

Brain Layer 雙軌 Registry 架構:
- 新建 src/services/ai_providers/ 目錄 (interfaces + 4 providers)
  - OllamaProvider (local, rca/chat/code_review)
  - GeminiProvider (cloud, rca/chat)
  - ClaudeProvider (cloud, rca/chat/code_review)
  - OpenClawNemoProvider (cloud, rca — 委派 188→NIM)
- 擴展 ai_router.py 加入:
  - AIProviderRegistry (動態註冊/啟停)
  - AIRouterExecutor (Cache + 閘門 CB/RL/Sem + 執行)
- openclaw.py 絞殺者包裝: USE_AI_ROUTER=true 走新路徑
- config.py + ConfigMap 加入 USE_AI_ROUTER=false (安全預設)
- ADR-052 正式文件 (14 項決策 D1-D14)
- HARD_RULES v1.7 加入 AI Router 規範

安全: USE_AI_ROUTER=false 預設不啟用，需手動開啟觀察
回滾: kubectl set env deployment/awoooi-api USE_AI_ROUTER=false

2026-04-02 ogt: Phase 24 首批實作

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

apps/api/src/core/config.py

@@ -52,6 +52,16 @@ class Settings(BaseSettings):
     )
 
     # ==========================================================================
+    # ==========================================================================
+    # Phase 24: AI Provider Registry (ADR-052)
+    # 2026-04-02 ogt: 絞殺者開關 — true=新 AIRouter, false=舊 openclaw.py if/else
+    # 回滾指令: kubectl set env deployment/awoooi-api USE_AI_ROUTER=false
+    # ==========================================================================
+    USE_AI_ROUTER: bool = Field(
+        default=False,
+        description="Phase 24: True=新 AIRouter 路由, False=舊 openclaw.py fallback chain",
+    )
+
     # Phase 22: OpenClaw + Nemotron 協作 (ADR-044)
     # 2026-03-31 Claude Code: 統帥批准實作
     #