docs: document plugin system

docs/plugins/voice-call.md

@@ -0,0 +1,96 @@
+---
+summary: "Voice Call plugin: Twilio-backed outbound calls (plugin install + config + CLI)"
+read_when:
+  - You want to place an outbound voice call from Clawdbot
+  - You are configuring or developing the voice-call plugin
+---
+
+# Voice Call (plugin)
+
+Outbound voice calls for Clawdbot via a plugin.
+
+Current providers:
+- `twilio` (real calls)
+- `log` (dev fallback; no network)
+
+If you haven’t read the general plugin docs yet, start with [Plugins](/plugin).
+
+## Install
+
+### Option A: install from npm (recommended)
+
+```bash
+clawdbot plugins install @clawdbot/voice-call
+```
+
+This downloads the package, extracts it into `~/.clawdbot/extensions/`, and enables it in `clawdbot.json`.
+
+Restart the Gateway afterwards.
+
+### Option B: install from a local folder (dev)
+
+```bash
+mkdir -p ~/.clawdbot/extensions
+cp -R extensions/voice-call ~/.clawdbot/extensions/voice-call
+cd ~/.clawdbot/extensions/voice-call && pnpm install
+```
+
+Restart the Gateway afterwards.
+
+## Config
+
+Set config under `plugins.entries.voice-call.config`:
+
+```json5
+{
+  plugins: {
+    entries: {
+      "voice-call": {
+        enabled: true,
+        config: {
+          provider: "twilio",
+          twilio: {
+            accountSid: "ACxxxxxxxx",
+            authToken: "…",
+            from: "+15551234567",
+            statusCallbackUrl: "https://example.com/twilio-status", // optional
+            twimlUrl: "https://example.com/twiml" // optional
+          }
+        }
+      }
+    }
+  }
+}
+```
+
+Dev fallback:
+
+```json5
+{ provider: "log" }
+```
+
+Notes:
+- `twilio.authToken` is treated as sensitive in the Control UI schema hints.
+
+## CLI
+
+```bash
+clawdbot voicecall start --to "+15555550123" --message "Hello from Clawdbot"
+clawdbot voicecall status --sid CAxxxxxxxx
+```
+
+## Agent tool
+
+Tool name: `voice_call`
+
+- `mode`: `"call" | "status"` (default: `call`)
+- `to`: required for `call`
+- `sid`: required for `status`
+- `message`: optional
+
+This repo ships a matching skill doc at `skills/voice-call/SKILL.md`.
+
+## Gateway RPC
+
+- `voicecall.start` (`to`, optional `message`)
+- `voicecall.status` (`sid`)