v2 host: portable desktop app (tray + FastAPI + WebView2 panel), unified config, HA control

Fold the Windows tray/daemon into one self-contained Clawdmeter.exe with a
settings UI, and wire the host side of the watch features:

- config.py: single %LOCALAPPDATA%\Clawdmeter\config.json (ha/buttons/settings),
  atomic writes, auto-migration from the old ha_config.json.
- server.py: local FastAPI (127.0.0.1:8723) — GET/PUT /api/config (token masked),
  POST /api/ha/test, GET /api/ha/entities, GET /api/status.
- web/index.html: brand-styled settings panel (Status/HA/Buttons/Settings tabs).
- panel.py: pywebview/WebView2 window, launched as its own process (pywebview and
  pystray both want the main thread); tray "Settings" opens it via --panel.
- daemon: HA command dispatch (toggle/bri/ct), dynamic button labels + index→
  action mapping, watch-battery low warning toast, and the dimmer "dim" snapshot
  (dimreq → light_snapshot of the first entity) so the watch dial seeds from HA.
- clawdmeter.spec / requirements: bundle fastapi+uvicorn+pywebview+webview backend.
- build-exe.ps1: ASCII-only (Windows PowerShell 5.1 mangles em-dashes under cp1251).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

daemon/panel.py

@@ -0,0 +1,97 @@
+#!/usr/bin/env python3
+"""WebView2 settings window for Clawdmeter (Phase 7, M1).
+
+Opens a native Windows WebView2 window (via pywebview) onto the local control
+panel the tray process already serves on 127.0.0.1. Launched as a SEPARATE
+PROCESS from the tray — ``Clawdmeter.exe --panel`` when frozen, ``python -m
+daemon.panel`` in source — because pywebview and pystray each need to own the
+main thread and cannot coexist in one process (see tray_windows._on_settings).
+
+The port comes from CLAWDMETER_PANEL_PORT (set by the tray when it spawns us)
+and falls back to the config default, so the window always points at the server
+the tray actually started.
+"""
+from __future__ import annotations
+
+import os
+import sys
+import time
+import urllib.request
+
+# Make the `daemon` package importable when run as a bare script or frozen exe,
+# mirroring tray_windows.py's bootstrap (logon autostart starts us with cwd =
+# System32, and the frozen exe loads the package from the bundle root).
+if getattr(sys, "frozen", False):
+    _REPO_ROOT = sys._MEIPASS  # type: ignore[attr-defined]
+else:
+    _REPO_ROOT = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
+if _REPO_ROOT not in sys.path:
+    sys.path.insert(0, _REPO_ROOT)
+
+_VENV_SITE = os.path.join(_REPO_ROOT, ".venv", "Lib", "site-packages")
+if os.path.isdir(_VENV_SITE):
+    import site
+    site.addsitedir(_VENV_SITE)
+
+try:
+    from daemon import config as cfgmod
+except ImportError:  # running as a plain script (cwd on path)
+    import config as cfgmod
+
+WINDOW_TITLE = "Clawdmeter"
+WINDOW_W = 860
+WINDOW_H = 720
+WINDOW_MIN = (640, 560)
+BRAND_BG = "#131211"   # paint the chrome brand-dark so there's no white flash
+
+
+def _port() -> int:
+    raw = os.environ.get("CLAWDMETER_PANEL_PORT")
+    if raw:
+        try:
+            return int(raw)
+        except ValueError:
+            pass
+    return cfgmod.DEFAULT_PORT
+
+
+def _wait_for_server(url: str, timeout: float = 6.0) -> bool:
+    """Poll the server's status endpoint until it answers or the timeout elapses.
+
+    The tray starts the HTTP server in a thread a moment before it can spawn us,
+    so a freshly-clicked Settings might briefly beat the socket. Polling avoids a
+    blank window in that race; a miss just means we open anyway and the UI's own
+    fetch retries.
+    """
+    deadline = time.time() + timeout
+    probe = url.rstrip("/") + "/api/status"
+    while time.time() < deadline:
+        try:
+            with urllib.request.urlopen(probe, timeout=1.0) as r:
+                if r.status == 200:
+                    return True
+        except Exception:
+            time.sleep(0.25)
+    return False
+
+
+def run() -> None:
+    """Open the control-panel window and block until the user closes it."""
+    import webview  # imported here so the tray never pays for it unless --panel
+
+    url = f"http://127.0.0.1:{_port()}/"
+    _wait_for_server(url)
+    webview.create_window(
+        WINDOW_TITLE, url,
+        width=WINDOW_W, height=WINDOW_H,
+        min_size=WINDOW_MIN,
+        background_color=BRAND_BG,
+    )
+    # gui defaults to auto-detect; on Windows 11 that resolves to EdgeChromium
+    # (WebView2), which ships with the OS — the modern engine the brand CSS needs.
+    # start() blocks on the native GUI loop until the window closes.
+    webview.start()
+
+
+if __name__ == "__main__":
+    run()