feat: add social links with validation and Font Awesome icons

Added comprehensive social links functionality to user profiles:

**New Social Platforms:**
- Website (full URL validation)
- GitHub (username format)
- Bluesky (handle format)
- LinkedIn (username format)
- Twitch (username format)
- YouTube (handle or channel ID format)
- Discord Server (invite code format)

**Features:**
- Database schema updated with 7 new optional social link fields
- Backend services and API routes updated to handle all social links
- Settings form with input fields and helpful validation hints
- Profile display with Font Awesome icons for each platform
- Regex validation patterns for all fields with visual feedback
- Green border for valid input, red border for invalid input
- All form inputs use consistent type="text" for uniform styling
- Discord accepts just invite code (constructs full URL automatically)

**Technical Changes:**
- Installed @fortawesome/angular-fontawesome with pinned versions
- Replaced emoji icons with proper Font Awesome components
- Added FontAwesomeModule to profile component
- Updated all User type interfaces across frontend and backend
- Updated UserService mappings in all methods
- Added comprehensive regex patterns matching platform requirements

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

package.json

@@ -35,6 +35,10 @@
     "@fastify/rate-limit": "10.3.0",
     "@fastify/sensible": "6.0.4",
     "@fastify/static": "9.0.0",
+    "@fortawesome/angular-fontawesome": "4.0.0",
+    "@fortawesome/fontawesome-svg-core": "7.2.0",
+    "@fortawesome/free-brands-svg-icons": "7.2.0",
+    "@fortawesome/free-solid-svg-icons": "7.2.0",
     "@nhcarrigan/logger": "1.1.1",
     "@prisma/client": "6.19.2",
     "dompurify": "3.3.1",