Initial RS-UV3A Starlight documentation site

Documentation for the HobbyPCB RS-UV3A tri-band FM transceiver board
covering 2m, 1.25m, and 70cm amateur radio bands.

Structure:
- Getting Started: quick start, connections, serial setup
- Guides: voice, packet/APRS, beacons, repeater/satellite, firmware
- Reference: specs, 66 serial commands, connector pinouts, hw revisions
- Accessories: RS-UVPA 5W power amplifier

Features:
- Ham radio green theme for readability
- Full command reference with categorization
- Searchable via Starlight/Pagefind
- Mobile responsive

.gitignore

@@ -0,0 +1,23 @@
+# Build output
+dist/
+
+# Node modules
+node_modules/
+
+# Environment
+.env
+.env.*
+!.env.example
+
+# IDE
+.idea/
+.vscode/
+*.swp
+*.swo
+
+# OS
+.DS_Store
+Thumbs.db
+
+# Astro
+.astro/