feat(web): mobile-responsive redesign with Library view and design tokens

Add mobile layout (mini player, bottom tab bar, responsive navbar), new
Library view, redesigned bot dropdown with action buttons, and centralize
colors/typography/shadows into CSS variables in variables.scss.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

.claude/settings.local.json

@@ -13,7 +13,10 @@
       "mcp__Claude_Preview__*",
       "mcp__Claude_in_Chrome__*",
       "mcp__scheduled-tasks__*",
-      "Bash(npx vitest:*)"
+      "Bash(npx vitest:*)",
+      "Bash(cp \"C:\\\\Users\\\\saopig1\\\\.claude\\\\projects\\\\C--Users-saopig1-Music-teamspeak-music-bot\\\\b5a64d6f-051e-4b87-966c-ece97d2b879b\\\\tool-results\\\\webfetch-1776569008470-exv7qe.bin\" /tmp/design.gz)",
+      "Bash(gunzip -f /tmp/design.gz)",
+      "Read(//tmp/**)"
     ],
     "deny": [
       "Bash(git push * main)",