fix: apply ruff auto-fixes and add hk git hooks

- Fix pre-existing lint errors in engine/ modules using ruff --unsafe-fixes
- Add hk.pkl with pre-commit and pre-push hooks using ruff builtin
- Configure hooks to use 'uv run' prefix for tool execution
- Update mise.toml to include hk and pkl tools
- All 73 tests pass

engine/ntfy.py

@@ -25,7 +25,7 @@ class NtfyPoller:
         self.topic_url = topic_url
         self.poll_interval = poll_interval
         self.display_secs = display_secs
-        self._message = None   # (title, body, monotonic_timestamp) or None
+        self._message = None  # (title, body, monotonic_timestamp) or None
         self._lock = threading.Lock()
 
     def start(self):
@@ -54,9 +54,12 @@ class NtfyPoller:
         while True:
             try:
                 req = urllib.request.Request(
-                    self.topic_url, headers={"User-Agent": "mainline/0.1"})
+                    self.topic_url, headers={"User-Agent": "mainline/0.1"}
+                )
                 resp = urllib.request.urlopen(req, timeout=10)
-                for line in resp.read().decode('utf-8', errors='replace').strip().split('\n'):
+                for line in (
+                    resp.read().decode("utf-8", errors="replace").strip().split("\n")
+                ):
                     if not line.strip():
                         continue
                     try: