Add dark/light theme toggle and Conectores section

- Add theme toggle button in TopMenu with Sun/Moon icons
- Save theme preference to localStorage
- Add dark mode CSS configuration with Tailwind @custom-variant
- Apply dark mode classes to Home.tsx, TopMenu, and connector pages
- Add new Conectores section in sidebar with Cable icon
- Create placeholder pages for SH-METERS, XMETERS, and TTS connectors
- Update App.tsx page types and routing

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/index.css

@@ -1 +1,23 @@
-@import 'tailwindcss'
+@import 'tailwindcss';
+
+/* Dark mode configuration */
+@custom-variant dark (&:where(.dark, .dark *));
+
+/* Base styles */
+:root {
+  color-scheme: light;
+}
+
+.dark {
+  color-scheme: dark;
+}
+
+/* Dark mode body */
+body {
+  @apply bg-slate-50 text-gray-900;
+}
+
+.dark body,
+body:where(.dark *) {
+  @apply bg-gray-900 text-gray-100;
+}