docs: add heartbeat example (partial #179)

examples/heartbeat/README.md

@@ -0,0 +1,64 @@
+# Heartbeat example
+
+The heartbeat runs on a fixed interval while the daemon is up. It nudges Claude to check reminders, follow-ups, and anything that needs a human ping — without you having to ask.
+
+## Enable in settings
+
+Add or merge this block in `.claude/claudeclaw/settings.json`:
+
+```json
+{
+  "heartbeat": {
+    "enabled": true,
+    "interval": 15,
+    "prompt": "prompts/HEARTBEAT.md",
+    "forwardToTelegram": false,
+    "excludeWindows": [
+      {
+        "days": [0, 6],
+        "start": "22:00",
+        "end": "08:00"
+      }
+    ]
+  },
+  "timeouts": {
+    "heartbeat": 15
+  }
+}
+```
+
+| Field | Meaning |
+|-------|---------|
+| `enabled` | Turn the heartbeat on or off |
+| `interval` | Minutes between runs |
+| `prompt` | Path to the prompt file (relative to project root) or inline text |
+| `forwardToTelegram` | When `true`, forward non-`HEARTBEAT_OK` output to Telegram |
+| `excludeWindows` | Optional quiet hours (local timezone from `timezone` in settings) |
+
+## Prompt template
+
+The built-in template lives at `prompts/heartbeat/HEARTBEAT.md` in the plugin. To customize it for your project, copy or author:
+
+`.claude/claudeclaw/prompts/HEARTBEAT.md`
+
+Project overrides fully replace the built-in template.
+
+## Start the daemon
+
+```bash
+/claudeclaw:start
+```
+
+Or from the CLI:
+
+```bash
+bun run src/index.ts start
+```
+
+Use `/claudeclaw:status` (or `bun run src/index.ts status`) to confirm the next heartbeat countdown.
+
+## Expected behavior
+
+- If nothing needs attention, Claude replies `HEARTBEAT_OK` and the daemon stays quiet (unless `forwardToTelegram` is on).
+- If something does need attention, output can be forwarded to configured messaging channels.
+- Heartbeat logs are written under `.claude/claudeclaw/logs/`.