refactor(plugins): move owner skills into plugins

Move Canvas, Discord, Slack, voice-call, and WhatsApp skill docs from the root bundled skill tree into their owning plugin packages, with manifest skills declarations and docs/test path updates.

Validation:
- node --import tsx scripts/sync-plugin-versions.ts --check
- node scripts/run-vitest.mjs src/skills/loading/env-path-guidance.test.ts
- autoreview clean
- Crabbox Azure pnpm check:changed run_59ba76511d57 / lease cbx_cbc6750dad72
- wrapper prepare passed pnpm install --frozen-lockfile, pnpm build, and pnpm check before the oversized full local pnpm test was stopped

Follow-up: #95132 remains as the stacked PR for the rest of the starter-skill/Sherpa/ClawHub work.

docs/plugins/reference/canvas.md

@@ -16,4 +16,4 @@ Experimental Canvas control and A2UI rendering surfaces for paired nodes.
 
 ## Surface
 
-contracts: tools
+contracts: tools; skills

docs/plugins/reference/discord.md

@@ -16,7 +16,7 @@ OpenClaw Discord channel plugin for channels, DMs, commands, and app events.
 
 ## Surface
 
-channels: discord; contracts: transcriptSourceProviders
+channels: discord; contracts: transcriptSourceProviders; skills
 
 ## Related docs
 

docs/plugins/reference/slack.md

@@ -16,7 +16,7 @@ OpenClaw Slack channel plugin for channels, DMs, commands, and app events.
 
 ## Surface
 
-channels: slack
+channels: slack; skills
 
 ## Related docs
 

docs/plugins/reference/voice-call.md

@@ -16,7 +16,7 @@ OpenClaw voice-call plugin for Twilio, Telnyx, and Plivo phone calls.
 
 ## Surface
 
-contracts: tools
+contracts: tools; skills
 
 ## Related docs
 

docs/plugins/reference/whatsapp.md

@@ -16,7 +16,7 @@ OpenClaw WhatsApp channel plugin for WhatsApp Web chats.
 
 ## Surface
 
-channels: whatsapp
+channels: whatsapp; skills
 
 ## Related docs
 

docs/plugins/voice-call.md

@@ -759,7 +759,7 @@ Tool name: `voice_call`.
 | `end_call`      | `callId`                                   |
 | `get_status`    | `callId`                                   |
 
-This repo ships a matching skill doc at `skills/voice-call/SKILL.md`.
+The voice-call plugin ships a matching agent skill.
 
 ## Gateway RPC
 

extensions/canvas/openclaw.plugin.json

@@ -6,6 +6,7 @@
   "enabledByDefault": true,
   "name": "Canvas",
   "description": "Experimental Canvas control and A2UI rendering surfaces for paired nodes.",
+  "skills": ["./skills"],
   "contracts": {
     "tools": ["canvas"]
   },

extensions/discord/openclaw.plugin.json

@@ -2,6 +2,7 @@
   "id": "discord",
   "name": "Discord",
   "description": "OpenClaw Discord channel plugin for channels, DMs, commands, and app events.",
+  "skills": ["./skills"],
   "activation": {
     "onStartup": false
   },

extensions/slack/openclaw.plugin.json

@@ -2,6 +2,7 @@
   "id": "slack",
   "name": "Slack",
   "description": "OpenClaw Slack channel plugin for channels, DMs, commands, and app events.",
+  "skills": ["./skills"],
   "activation": {
     "onStartup": false
   },

extensions/voice-call/openclaw.plugin.json

@@ -2,6 +2,7 @@
   "id": "voice-call",
   "name": "Voice Call",
   "description": "OpenClaw voice-call plugin for Twilio, Telnyx, and Plivo phone calls.",
+  "skills": ["./skills"],
   "commandAliases": [{ "name": "voicecall" }],
   "activation": {
     "onStartup": true,

extensions/whatsapp/openclaw.plugin.json

@@ -2,6 +2,7 @@
   "id": "whatsapp",
   "name": "WhatsApp",
   "description": "OpenClaw WhatsApp channel plugin for WhatsApp Web chats.",
+  "skills": ["./skills"],
   "activation": {
     "onStartup": false
   },

src/skills/loading/env-path-guidance.test.ts

@@ -27,7 +27,7 @@ const CASES: GuidanceCase[] = [
     forbidden: ["cat ~/.openclaw/openclaw.json"],
   },
   {
-    file: "skills/canvas/SKILL.md",
+    file: "extensions/canvas/skills/canvas/SKILL.md",
     required: ["OPENCLAW_CONFIG_PATH"],
     forbidden: ["cat ~/.openclaw/openclaw.json"],
   },