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-queue/spec.md

@@ -0,0 +1,16 @@
+## ADDED Requirements
+
+### Requirement: 排期队列操作函数迁移至独立模块
+系统 SHALL 将内容排期队列相关函数从 `main.py` 提取至 `services/queue_ops.py`，包括：`generate_to_queue`、`_queue_publish_callback`、`queue_refresh_table`、`queue_refresh_calendar`、`queue_preview_item`、`queue_approve_item`、`queue_reject_item`、`queue_delete_item`、`queue_retry_item`、`queue_publish_now`、`queue_start_processor`、`queue_stop_processor`、`queue_get_status`、`queue_batch_approve`、`queue_generate_and_refresh`。
+
+#### Scenario: 模块导入成功
+- **WHEN** `main.py` 执行 `from services.queue_ops import queue_generate_and_refresh, queue_refresh_table` 等导入
+- **THEN** 所有函数可正常调用
+
+#### Scenario: publish callback 在 main.py 完成注册
+- **WHEN** 应用启动时 `main.py` 调用 `pub_queue.set_publish_callback(_queue_publish_callback)`（`_queue_publish_callback` 已迁移至 `queue_ops.py`）
+- **THEN** 队列发布回调 SHALL 正常注册并在队列处理时触发
+
+#### Scenario: 队列操作读写 pub_queue 单例
+- **WHEN** `queue_ops.py` 中的函数需要访问 `pub_queue` 或 `queue_publisher`
+- **THEN** 这些单例 SHALL 通过函数参数传入，不在 `queue_ops.py` 模块顶层初始化