Add native Windows host daemon (bleak/WinRT)

Adds a Windows port of the host daemon so the Clawdmeter stays connected
on Windows independent of WSL. Mirrors the macOS daemon and speaks the
existing GATT data service unchanged — no firmware changes.

- claude_usage_daemon_windows.py: Windows-local OAuth token read +
  Anthropic poll + BLE scan/connect/write, with auto-reconnect
  (connect-retry wrapper, zombie-link break, split fast/slow backoff)
- tray_windows.py: pystray login-startup tray app (status icon + Quit)
- autostart_windows.py: winreg HKCU\Run autostart via pythonw.exe
- icon_assets.py: per-state tray icons composited from logo.h
- install-windows.ps1 + daemon/README-windows.md: turnkey setup
- pytest suite: token / poll / reconnect / tray / autostart / no-WSL guard

daemon/autostart_windows.py

@@ -0,0 +1,108 @@
+"""Login-autostart toggle for Clawdmeter — APP-01 / D-07.
+
+Manages a per-user HKCU\\Software\\Microsoft\\Windows\\CurrentVersion\\Run
+registry value named "Clawdmeter" that launches the tray app headlessly via
+pythonw.exe (no console window — D-08).
+
+winreg is Windows stdlib; this module guards the import so it can be imported
+on the Linux dev box (unit tests mock `daemon.autostart_windows.winreg`).
+
+Public API:
+  enable(tray_script=None)  -- write/overwrite the Run value
+  disable()                 -- remove the Run value; idempotent when absent
+  is_enabled()              -- True if the Run value is currently present
+"""
+
+import os
+import sys
+import time
+
+# Guard the import so the module is importable off-Windows.
+# Unit tests replace this attribute via:
+#   patch("daemon.autostart_windows.winreg", <MagicMock>)
+try:
+    import winreg as winreg  # type: ignore[import]
+except ImportError:
+    winreg = None  # type: ignore[assignment]
+
+# Registry key (no leading backslash — OpenKey uses relative path under hive).
+_RUN_KEY = r"Software\Microsoft\Windows\CurrentVersion\Run"
+_VALUE_NAME = "Clawdmeter"
+
+
+def log(msg: str) -> None:
+    """Log in the daemon [HH:MM:SS] style."""
+    print(f"[{time.strftime('%H:%M:%S')}] {msg}", flush=True)
+
+
+def _command(tray_script: str | None = None) -> str:
+    """Build the headless launch command for the Run value.
+
+    Uses the BASE interpreter's pythonw.exe — `sys.base_exec_prefix` points at
+    the real Python install even inside a venv — NOT the venv's
+    `Scripts\\pythonw.exe`.  The venv pythonw is a redirector stub that
+    re-launches the CONSOLE `python.exe` build as a child process (a CPython
+    venv-launcher bug, verified empirically on Python 3.13), which pops a black
+    console window at logon and kills the tray when closed (field bug, SC#1).
+    The base pythonw loads in-process and is genuinely windowless.
+
+    The path is never hard-coded (D-08, CLAUDE.md "repoint ExecStart" lesson);
+    both paths are quoted for space safety.  tray_windows.py adds the venv's
+    site-packages to sys.path itself, so the venv's deps still resolve under the
+    base interpreter.
+
+    Args:
+        tray_script: absolute path to the tray entry script.  Defaults to this
+                     module's own path (useful when autostart_windows.py IS
+                     the entry point, but callers should pass tray_windows.py).
+    """
+    pythonw = os.path.join(sys.base_exec_prefix, "pythonw.exe")
+    script = os.path.abspath(tray_script if tray_script is not None else __file__)
+    return f'"{pythonw}" "{script}"'
+
+
+def enable(tray_script: str | None = None) -> None:
+    """Write (or overwrite) the HKCU Run value pointing at pythonw.exe.
+
+    No admin elevation required — HKCU is per-user (D-07, ASVS V4).
+
+    Args:
+        tray_script: path to the tray entry script (passed to _command()).
+    """
+    cmd = _command(tray_script)
+    with winreg.OpenKey(
+        winreg.HKEY_CURRENT_USER, _RUN_KEY, 0, winreg.KEY_SET_VALUE
+    ) as key:
+        winreg.SetValueEx(key, _VALUE_NAME, 0, winreg.REG_SZ, cmd)
+    log(f"Autostart enabled: {cmd}")
+
+
+def disable() -> None:
+    """Remove the HKCU Run value.  Idempotent — no error if already absent.
+
+    Mirrors the read_token() OSError-swallow pattern (daemon L201-208).
+    """
+    try:
+        with winreg.OpenKey(
+            winreg.HKEY_CURRENT_USER, _RUN_KEY, 0, winreg.KEY_SET_VALUE
+        ) as key:
+            winreg.DeleteValue(key, _VALUE_NAME)
+        log("Autostart disabled")
+    except FileNotFoundError:
+        pass  # already absent — idempotent
+
+
+def is_enabled() -> bool:
+    """Return True if the Run value is currently present, False otherwise.
+
+    Queries the live registry on every call so the state reflects external
+    changes (e.g. the user deleting the value manually) — Pitfall 6 guard.
+    """
+    try:
+        with winreg.OpenKey(
+            winreg.HKEY_CURRENT_USER, _RUN_KEY, 0, winreg.KEY_QUERY_VALUE
+        ) as key:
+            winreg.QueryValueEx(key, _VALUE_NAME)
+            return True
+    except FileNotFoundError:
+        return False