iMessage: promote BlueBubbles and refresh docs/skills (#8415)

* feat: Make BlueBubbles the primary iMessage integration

- Remove old imsg skill (skills/imsg/SKILL.md)
- Create new BlueBubbles skill (skills/bluebubbles/SKILL.md) with message tool examples
- Add keep-alive script documentation for VM/headless setups to docs/channels/bluebubbles.md
  - AppleScript that pokes Messages.app every 5 minutes
  - LaunchAgent configuration for automatic execution
  - Prevents Messages.app from going idle in VM environments
- Update all documentation to prioritize BlueBubbles over legacy imsg:
  - Mark imsg channel as legacy throughout docs
  - Update README.md channel lists
  - Update wizard, hubs, pairing, and index docs
  - Update FAQ to recommend BlueBubbles for iMessage
  - Update RPC docs to note imsg as legacy pattern
  - Update Chinese documentation (zh-CN)
- Replace imsg examples with generic macOS skill examples where appropriate

BlueBubbles is now the recommended first-class iMessage integration,
with the legacy imsg integration marked for potential future removal.

* refactor: Update import paths and improve code formatting

- Adjusted import paths in session-status-tool.ts, whatsapp-heartbeat.ts, and heartbeat-runner.ts for consistency.
- Reformatted code for better readability by aligning and grouping related imports and function parameters.
- Enhanced error messages and conditional checks for clarity in heartbeat-runner.ts.

* skills: restore imsg skill and align bluebubbles skill

* docs: update FAQ for clarity and formatting

- Adjusted the formatting of the FAQ section to ensure consistent bullet point alignment.
- No content changes were made, only formatting improvements for better readability.

* style: oxfmt touched files

* fix: preserve BlueBubbles developer reference (#8415) (thanks @tyler6204)

docs/zh-CN/channels/index.md

@@ -28,8 +28,8 @@ OpenClaw 可以在你已经使用的任何聊天应用上与你交流。每个
 - [Google Chat](/channels/googlechat) — 通过 HTTP webhook 的 Google Chat API 应用。
 - [Mattermost](/channels/mattermost) — Bot API + WebSocket；频道、群组、私信（插件，需单独安装）。
 - [Signal](/channels/signal) — signal-cli；注重隐私。
-- [BlueBubbles](/channels/bluebubbles) — **iMessage 推荐方案**；使用 BlueBubbles macOS 服务器 REST API，完整功能支持（编辑、撤回、特效、表情回应、群组管理——编辑功能目前在 macOS 26 Tahoe 上存在问题）。
-- [iMessage](/channels/imessage) — 仅限 macOS；通过 imsg 原生集成（旧版方案，新部署建议使用 BlueBubbles）。
+- [BlueBubbles](/channels/bluebubbles) — **推荐用于 iMessage**；使用 BlueBubbles macOS 服务器 REST API，功能完整（编辑、撤回、特效、回应、群组管理——编辑功能在 macOS 26 Tahoe 上目前不可用）。
+- [iMessage（旧版）](/channels/imessage) — 通过 imsg CLI 的旧版 macOS 集成（已弃用，新设置请使用 BlueBubbles）。
 - [Microsoft Teams](/channels/msteams) — Bot Framework；企业支持（插件，需单独安装）。
 - [LINE](/channels/line) — LINE Messaging API 机器人（插件，需单独安装）。
 - [Nextcloud Talk](/channels/nextcloud-talk) — 通过 Nextcloud Talk 的自托管聊天（插件，需单独安装）。