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/settings.css

@@ -0,0 +1,117 @@
+*,
+*::before,
+*::after {
+	box-sizing: border-box;
+	margin: 0;
+	padding: 0;
+}
+body {
+	font-family:
+		-apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
+	background: #1a1a1a;
+	color: #e0e0e0;
+	display: flex;
+	justify-content: center;
+	align-items: center;
+	min-height: 100vh;
+	padding: 20px;
+}
+.container {
+	background: #2a2a2a;
+	border-radius: 12px;
+	padding: 32px;
+	width: 100%;
+	max-width: 480px;
+	box-shadow: 0 4px 24px rgba(0, 0, 0, 0.4);
+}
+h1 {
+	font-size: 1.5rem;
+	margin-bottom: 4px;
+	color: #fff;
+}
+.subtitle {
+	font-size: 0.85rem;
+	color: #888;
+	margin-bottom: 24px;
+}
+.field {
+	margin-bottom: 18px;
+}
+label {
+	display: block;
+	font-size: 0.8rem;
+	font-weight: 600;
+	text-transform: uppercase;
+	letter-spacing: 0.05em;
+	color: #aaa;
+	margin-bottom: 6px;
+}
+input,
+select {
+	width: 100%;
+	padding: 10px 12px;
+	background: #1a1a1a;
+	border: 1px solid #444;
+	border-radius: 6px;
+	color: #e0e0e0;
+	font-size: 0.95rem;
+	outline: none;
+	transition: border-color 0.15s;
+}
+input:focus,
+select:focus {
+	border-color: #5b9aff;
+}
+input::placeholder {
+	color: #555;
+}
+.hint {
+	font-size: 0.75rem;
+	color: #666;
+	margin-top: 4px;
+}
+.actions {
+	display: flex;
+	gap: 10px;
+	margin-top: 24px;
+}
+button {
+	flex: 1;
+	padding: 10px 16px;
+	border: none;
+	border-radius: 6px;
+	font-size: 0.9rem;
+	font-weight: 600;
+	cursor: pointer;
+	transition: opacity 0.15s;
+}
+button:hover {
+	opacity: 0.85;
+}
+#save-btn {
+	background: #5b9aff;
+	color: #000;
+}
+#reset-btn {
+	background: #444;
+	color: #e0e0e0;
+}
+.status {
+	margin-top: 14px;
+	padding: 10px 12px;
+	border-radius: 6px;
+	font-size: 0.85rem;
+	display: none;
+}
+.status.success {
+	display: block;
+	background: #1a3a1a;
+	color: #6fcf6f;
+	border: 1px solid #2a5a2a;
+}
+.status.error {
+	display: block;
+	background: #3a1a1a;
+	color: #cf6f6f;
+	border: 1px solid #5a2a2a;
+}