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)

src/agents/tools/session-status-tool.ts

@@ -1,22 +1,6 @@
 import { Type } from "@sinclair/typebox";
 import type { OpenClawConfig } from "../../config/config.js";
 import type { AnyAgentTool } from "./common.js";
-import { resolveAgentDir } from "../../agents/agent-scope.js";
-import {
-  ensureAuthProfileStore,
-  resolveAuthProfileDisplayLabel,
-  resolveAuthProfileOrder,
-} from "../../agents/auth-profiles.js";
-import { getCustomProviderApiKey, resolveEnvApiKey } from "../../agents/model-auth.js";
-import { loadModelCatalog } from "../../agents/model-catalog.js";
-import {
-  buildAllowedModelSet,
-  buildModelAliasIndex,
-  modelKey,
-  normalizeProviderId,
-  resolveDefaultModelForAgent,
-  resolveModelRefFromString,
-} from "../../agents/model-selection.js";
 import { normalizeGroupActivation } from "../../auto-reply/group-activation.js";
 import { getFollowupQueueDepth, resolveQueueSettings } from "../../auto-reply/reply/queue.js";
 import { buildStatusMessage } from "../../auto-reply/status.js";
@@ -39,7 +23,23 @@ import {
   resolveAgentIdFromSessionKey,
 } from "../../routing/session-key.js";
 import { applyModelOverrideToSessionEntry } from "../../sessions/model-overrides.js";
+import { resolveAgentDir } from "../agent-scope.js";
+import {
+  ensureAuthProfileStore,
+  resolveAuthProfileDisplayLabel,
+  resolveAuthProfileOrder,
+} from "../auth-profiles.js";
 import { formatUserTime, resolveUserTimeFormat, resolveUserTimezone } from "../date-time.js";
+import { getCustomProviderApiKey, resolveEnvApiKey } from "../model-auth.js";
+import { loadModelCatalog } from "../model-catalog.js";
+import {
+  buildAllowedModelSet,
+  buildModelAliasIndex,
+  modelKey,
+  normalizeProviderId,
+  resolveDefaultModelForAgent,
+  resolveModelRefFromString,
+} from "../model-selection.js";
 import { readStringParam } from "./common.js";
 import {
   shouldResolveSessionIdInput,