fix: watch presence.json and broadcast state via WS (#379)

Co-authored-by: Kimi Agent <kimi@timmy.local>
Co-committed-by: Kimi Agent <kimi@timmy.local>

tests/integrations/test_presence_watcher.py

@@ -0,0 +1,95 @@
+"""Tests for the presence file watcher in dashboard.app."""
+
+import asyncio
+import json
+from unittest.mock import AsyncMock, patch
+
+import pytest
+
+# Common patches to eliminate delays and inject mock ws_manager
+_FAST = {
+    "dashboard.app._PRESENCE_POLL_SECONDS": 0.01,
+    "dashboard.app._PRESENCE_INITIAL_DELAY": 0,
+}
+
+
+def _patches(mock_ws, presence_file):
+    """Return a combined context manager for presence watcher patches."""
+    from contextlib import ExitStack
+
+    stack = ExitStack()
+    stack.enter_context(patch("dashboard.app._PRESENCE_FILE", presence_file))
+    stack.enter_context(patch("infrastructure.ws_manager.handler.ws_manager", mock_ws))
+    for key, val in _FAST.items():
+        stack.enter_context(patch(key, val))
+    return stack
+
+
+@pytest.mark.asyncio
+async def test_presence_watcher_broadcasts_on_file_change(tmp_path):
+    """Watcher reads presence.json and broadcasts via ws_manager."""
+    from dashboard.app import _presence_watcher
+
+    presence_file = tmp_path / "presence.json"
+    state = {
+        "version": 1,
+        "liveness": "2026-03-18T21:47:12Z",
+        "current_focus": "Reviewing PR #267",
+        "mood": "focused",
+    }
+    presence_file.write_text(json.dumps(state))
+
+    mock_ws = AsyncMock()
+
+    with _patches(mock_ws, presence_file):
+        task = asyncio.create_task(_presence_watcher())
+        await asyncio.sleep(0.15)
+        task.cancel()
+        try:
+            await task
+        except asyncio.CancelledError:
+            pass
+
+    mock_ws.broadcast.assert_called_with("timmy_state", state)
+
+
+@pytest.mark.asyncio
+async def test_presence_watcher_synthesised_state_when_missing(tmp_path):
+    """Watcher broadcasts synthesised idle state when file is absent."""
+    from dashboard.app import _SYNTHESIZED_STATE, _presence_watcher
+
+    missing_file = tmp_path / "no-such-file.json"
+    mock_ws = AsyncMock()
+
+    with _patches(mock_ws, missing_file):
+        task = asyncio.create_task(_presence_watcher())
+        await asyncio.sleep(0.15)
+        task.cancel()
+        try:
+            await task
+        except asyncio.CancelledError:
+            pass
+
+    mock_ws.broadcast.assert_called_with("timmy_state", _SYNTHESIZED_STATE)
+
+
+@pytest.mark.asyncio
+async def test_presence_watcher_handles_bad_json(tmp_path):
+    """Watcher logs warning on malformed JSON and doesn't crash."""
+    from dashboard.app import _presence_watcher
+
+    presence_file = tmp_path / "presence.json"
+    presence_file.write_text("{bad json!!!")
+    mock_ws = AsyncMock()
+
+    with _patches(mock_ws, presence_file):
+        task = asyncio.create_task(_presence_watcher())
+        await asyncio.sleep(0.15)
+        task.cancel()
+        try:
+            await task
+        except asyncio.CancelledError:
+            pass
+
+    # Should not have broadcast anything on bad JSON
+    mock_ws.broadcast.assert_not_called()