fix(daemon): identify our daemon on Windows via CIM, not ps

src/claude_statusbar/daemon.py

@@ -343,16 +343,56 @@ def _cmdline_is_our_daemon(cmdline: str) -> bool:
     )
 
 
+_WIN_CMDLINE_TIMEOUT_S = 8.0
+
+
+def _win_process_cmdline(pid: int) -> Optional[str]:
+    """Command line of `pid` on Windows, or None if it can't be read.
+
+    Windows has no /proc, and `ps` is worse than useless there: when Git Bash
+    is on PATH its MSYS `ps` only lists MSYS processes, so a natively spawned
+    daemon reads as gone and the caller concludes "not ours".
+
+    CIM is the reliable source. `wmic` would be faster but is deprecated and
+    already absent from current Windows 11 builds. ~0.5s per call, which only
+    the stop / install / drift-restart paths pay — never a render.
+    """
+    import subprocess
+    script = (
+        f"$p = Get-CimInstance Win32_Process -Filter 'ProcessId={int(pid)}';"
+        "if ($p) { $p.CommandLine }"
+    )
+    for exe in ("powershell", "pwsh"):
+        try:
+            out = subprocess.run(
+                [exe, "-NoProfile", "-NonInteractive", "-Command", script],
+                capture_output=True,
+                text=True,
+                timeout=_WIN_CMDLINE_TIMEOUT_S,
+                creationflags=getattr(subprocess, "CREATE_NO_WINDOW", 0),
+            )
+        except (OSError, subprocess.TimeoutExpired):
+            continue  # not installed / hung — try the next interpreter
+        if out.returncode == 0 and out.stdout.strip():
+            return out.stdout
+    return None
+
+
 def _process_is_our_daemon(pid: int) -> bool:
     """Verify the PID actually belongs to *our* daemon, not a recycled PID.
 
     Linux: read /proc/<pid>/cmdline directly (cheap, no fork).
+    Windows: query CIM (see `_win_process_cmdline`).
     macOS / fallback: shell out to `ps -o command= -p <pid>` (~10ms — only
     runs on stop/install paths, never on the per-render hot path).
 
     Returns False on any error (better to assume not-ours and skip than to
     accidentally SIGTERM an unrelated user process).
     """
+    if sys.platform == "win32":
+        cmdline = _win_process_cmdline(pid)
+        return _cmdline_is_our_daemon(cmdline) if cmdline else False
+
     proc_path = f"/proc/{pid}/cmdline"
     try:
         with open(proc_path, "rb") as f:

tests/test_daemon.py

@@ -1045,3 +1045,56 @@ def test_release_pidfile_still_cleans_its_own_file(monkeypatch, tmp_path: Path):
     assert _d._acquire_pidfile() is True
     _d._release_pidfile()
     assert not _d.pid_path().exists()
+
+
+def test_windows_identity_uses_cim_not_ps(monkeypatch):
+    """On Windows there is no /proc, and a Git-Bash `ps` on PATH only lists
+    MSYS processes — a natively spawned daemon reads as gone, so `cs daemon
+    stop` refuses to stop it and the drift-kill guard never restarts it onto
+    upgraded code."""
+    import subprocess as _sp
+
+    calls = []
+
+    def fake_run(cmd, **kw):
+        calls.append(cmd[0])
+        if cmd[0] == "ps":
+            raise AssertionError("ps must not be consulted on win32")
+        return _sp.CompletedProcess(
+            cmd, 0,
+            stdout=('"C:\Python\python.exe" -m claude_statusbar.cli '
+                    'daemon _run --render-interval 1.0\n'),
+            stderr="",
+        )
+
+    monkeypatch.setattr(sys, "platform", "win32")
+    monkeypatch.setattr(_sp, "run", fake_run)
+
+    assert _d._process_is_our_daemon(4242) is True
+    assert calls and calls[0] in ("powershell", "pwsh")
+
+
+def test_windows_identity_false_when_pid_is_someone_else(monkeypatch):
+    import subprocess as _sp
+
+    monkeypatch.setattr(sys, "platform", "win32")
+    monkeypatch.setattr(
+        _sp, "run",
+        lambda cmd, **kw: _sp.CompletedProcess(
+            cmd, 0, stdout="C:\Windows\explorer.exe\n", stderr=""),
+    )
+
+    assert _d._process_is_our_daemon(4242) is False
+
+
+def test_windows_identity_false_when_no_shell_available(monkeypatch):
+    """No powershell and no pwsh — stay conservative, never SIGTERM."""
+    import subprocess as _sp
+
+    monkeypatch.setattr(sys, "platform", "win32")
+    monkeypatch.setattr(
+        _sp, "run",
+        lambda cmd, **kw: (_ for _ in ()).throw(FileNotFoundError(cmd[0])),
+    )
+
+    assert _d._process_is_our_daemon(4242) is False