refactor: split monolithic main.py into services/ + ui/ modules (improve-maintainability)

- main.py: 4360 → 146 lines (96.6% reduction), entry layer only
- services/: rate_limiter, autostart, persona, connection, profile,
  hotspot, content, engagement, scheduler, queue_ops (10 business modules)
- ui/app.py: all Gradio UI code extracted into build_app(cfg, analytics)
- Fix: with gr.Blocks() indented inside build_app function
- Fix: cfg.all property (not get_all method)
- Fix: STATUS_LABELS, get_persona_keywords, fetch_proactive_notes imports
- Fix: queue_ops module-level set_publish_callback moved into configure()
- Fix: pub_queue.format_*() wrapped as queue_format_table/calendar helpers
- All 14 files syntax-verified, build_app() runtime-verified
- 58/58 tasks complete"

openspec/changes/improve-maintainability/specs/services-engagement/spec.md

@@ -0,0 +1,16 @@
+## ADDED Requirements
+
+### Requirement: 互动自动化函数迁移至独立模块
+系统 SHALL 将评论、点赞、收藏、回复等互动自动化函数从 `main.py` 提取至 `services/engagement.py`，包括：`load_note_for_comment`、`ai_generate_comment`、`send_comment`、`fetch_my_notes`、`on_my_note_selected`、`fetch_my_note_comments`、`ai_reply_comment`、`send_reply`、`auto_comment_once`、`_auto_comment_with_log`、`auto_like_once`、`_auto_like_with_log`、`auto_favorite_once`、`_auto_favorite_with_log`、`auto_reply_once`、`_auto_reply_with_log`、`_auto_publish_with_log`。
+
+#### Scenario: 模块导入成功
+- **WHEN** `main.py` 执行 `from services.engagement import auto_comment_once, auto_like_once` 等导入
+- **THEN** 所有函数可正常调用
+
+#### Scenario: 日志回调参数化
+- **WHEN** `engagement.py` 中的 `_with_log` 函数需要追加日志时
+- **THEN** 函数 SHALL 接收 `log_fn` 参数（callable）用于写入日志，不直接依赖外部 `_auto_log` 列表
+
+#### Scenario: 频率限制集成
+- **WHEN** `auto_comment_once` 等函数执行前需要检查每日限额和冷却状态
+- **THEN** 通过调用 `rate_limiter` 模块中的函数实现，不在 `engagement.py` 内复制限流逻辑