feat: AI Self-Loop 專案骨架 — 爬站健檢版

完整實作建構順序 1-8（rule-based）：
- Task Queue（SQLite）：tasks/attempts/results + claim 防重複
- LLM 後端：OllamaBackend(num_ctx=32768) + LLMRouter
- Prompt Builder（YAML+Jinja2，重試注入 feedback）
- Context Assembler / Output Judge / Feedback Builder
- Loop Controller + Circuit Breaker
- Driver 層（BaseDriver + ApiClientDriver）
- Agent 層（BaseAgent + SiteHealthAgent：爬站/健檢/issue 生成）
- pipeline.py 入口，驗收：pending→done，output/ 落地

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

.gitignore

@@ -0,0 +1,15 @@
+__pycache__/
+*.pyc
+.venv/
+venv/
+
+# Runtime artifacts
+*.db
+*.sqlite3
+output/*
+!output/.gitkeep
+review_queue/*
+!review_queue/.gitkeep
+
+# Real credentials never get committed; only the .example file does
+config/credentials.yaml