Add OpenTTD and Terraria support, improve config editors

- Add OpenTTD server integration (config editor, server card, API)
- Add Terraria server integration (config editor, API)
- Add legends to all config editors for syntax highlighting
- Simplify UserManagement: remove edit/delete buttons, add Discord avatars
- Add auto-logout on 401/403 API errors
- Update save button styling with visible borders

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

gsm-frontend/src/components/ServerCard.jsx

@@ -35,6 +35,20 @@ const serverInfo = {
     links: [
       { label: 'Steam', url: 'https://store.steampowered.com/app/1623730/Palworld/' }
     ]
+  },
+  terraria: {
+    address: 'terraria.zeasy.dev:7777',
+    logo: '/terraria.png',
+    links: [
+      { label: 'Steam', url: 'https://store.steampowered.com/app/105600/Terraria/' }
+    ]
+  },
+  openttd: {
+    address: 'openttd.zeasy.dev:3979',
+    logo: '/openttd.png',
+    links: [
+      { label: 'Steam', url: 'https://store.steampowered.com/app/1536610/OpenTTD/' }
+    ]
   }
 }
 
@@ -45,6 +59,8 @@ const getServerInfo = (serverName) => {
   if (name.includes('vrising') || name.includes('v rising')) return serverInfo.vrising
   if (name.includes('zomboid')) return serverInfo.zomboid
   if (name.includes('palworld')) return serverInfo.palworld
+  if (name.includes('terraria')) return serverInfo.terraria
+  if (name.includes('openttd')) return serverInfo.openttd
   return null
 }