feat: implement server password login, YouTube source, and improved bot selector UI

- **TS server password** (#7/#9): add serverPassword field across database,
  manager, bot API, and Settings UI — allows joining password-protected servers
- **YouTube audio source** (#1/#10): new YouTubeProvider using yt-dlp binary;
  adds -y flag in chat commands, /api/music supports platform=youtube,
  YouTube badge in SongCard, yt-dlp-wrap npm dependency
- **Bot selector UI** (#14): selector always visible (not just when >1 bot),
  bigger button with border and play-state indicator; per-bot URL routing at
  /bot/:id with BotRedirect view; copy-link button in dropdown

Closes #1, #7, #9, #10, #14

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

web/src/router/index.ts

@@ -38,6 +38,12 @@ const router = createRouter({
       name: 'setup',
       component: () => import('../views/Setup.vue'),
     },
+    {
+      // Per-bot URL: /bot/:id — sets active bot then redirects to home
+      path: '/bot/:id',
+      name: 'bot',
+      component: () => import('../views/BotRedirect.vue'),
+    },
   ],
 });