fix: broaden _mine_already_running catch — Windows os.kill raises plain OSError

On Windows, os.kill(bogus_pid, 0) raises OSError[WinError 87]
"The parameter is incorrect" — NOT ProcessLookupError. The old
except tuple missed it, so test_mine_already_running_dead_pid
failed on Windows CI.

Catching OSError covers ProcessLookupError + PermissionError +
FileNotFoundError on POSIX and WinError 87 on Windows. ValueError
still guards the int() parse.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

mempalace/hooks_cli.py

@@ -159,7 +159,10 @@ def _mine_already_running() -> bool:
         pid = int(_MINE_PID_FILE.read_text().strip())
         os.kill(pid, 0)  # signal 0 = existence check, no actual signal sent
         return True
-    except (FileNotFoundError, ValueError, ProcessLookupError, PermissionError):
+    except (OSError, ValueError):
+        # OSError covers: FileNotFoundError (no pid file), ProcessLookupError
+        # (dead PID on POSIX), PermissionError (not our process), and
+        # WinError 87 / "invalid parameter" (dead or unknown PID on Windows).
         return False