Add settings page, PIN manager, and auto-config

- New settings page at /settings (localhost-only) accessible via tray icon
- PIN manager with 6-digit codes, 5-min TTL, single-use
- API token uses secrets.token_urlsafe(32) for 256-bit entropy
- Config auto-creates config.yaml on first run with detected local IP
- Default PIN and token generated randomly on first startup
- Added pin_ttl setting (default 300s)
- Updated build_exe.py for onefile exe with settings assets bundled
- Added start.bat and start.sh for easy development startup

server/build_exe.py

@@ -36,7 +36,10 @@ a = Analysis(
     ["tray_wrapper.py"],
     pathex=[],
     binaries=[],
-    datas=[],
+    datas=[
+        ("settings.html", "."),
+        ("settings.css", "."),
+    ],
     hiddenimports=[
         "fastapi",
         "uvicorn",
@@ -48,6 +51,7 @@ a = Analysis(
         "notifications",
         "telemetry",
         "main",
+        "yaml",
     ],
     hookspath=[],
     hooksconfig={{}},
@@ -81,6 +85,7 @@ exe = EXE(
     codesign_identity=None,
     entitlements_file=None,
     icon=None,
+    onefile=True,
 )
 '''