docs: 文档清理与重构 — 统一为 3 个核心文档

- 删除 5 个过时/残留文档(project_plan/agent_prompt/optimization_plan/report_db_design/deploy/README)
- 新建 docs/architecture.md(项目架构:11 包职责+数据模型+配置+产物)
- 重写 docs/user-guide.md(CLI 全量+增量/断点续跑+MCP+FAQ)
- 重写 README.md(精简入口+文档索引)
- 更新 continuation.md(追加本次记录)
- 更新 .gitignore(排除 data/* 运行产物)

tests/conftest.py

@@ -0,0 +1,34 @@
+"""pytest 共享 fixture。"""
+
+from __future__ import annotations
+
+from pathlib import Path
+
+import pytest
+
+
+@pytest.fixture
+def sample_sources_yaml(tmp_path: Path) -> Path:
+    """生成最小可用 sources.yaml 用于测试。"""
+    content = """
+settings:
+  concurrency: 2
+  retry_max_attempts: 2
+  retry_min_wait_sec: 0.01
+  retry_max_wait_sec: 0.02
+  headless: true
+  output_root: data/raw
+
+sources:
+  - id: testsrc
+    name: 测试源
+    enabled: true
+    homepage: https://example.com/list
+    article_url_pattern: '^https://example\\.com/article/\\d+$'
+    js_render: false
+    page_timeout_ms: 5000
+    max_articles_per_run: 5
+"""
+    p = tmp_path / "sources.yaml"
+    p.write_text(content, encoding="utf-8")
+    return p