fix: bookmark widget sizing, generic globe icon, code-server brand icon

- multi-link bookmark cards now span 4/2 (matching the system widget)
  instead of 3/1, so they're not cramped and line up into an even
  3-up row alongside it
- the link list scrolls internally instead of stretching the card,
  so widgets in the same row stay equal height regardless of link count
- BrandIcon gains a small "generic icon" escape hatch (currently just
  `globe`, via phosphor) for widgets that don't have a real brand mark
- added a `coder` brand icon (Coder/code-server) for the Code Server link,
  since simple-icons has no official VS Code mark to use

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01WpxhtQY3CExQdMs4j7MmJe

scripts/extract-brand-icons.py

@@ -26,6 +26,7 @@ ICONS = {
     "postgresql": "postgresql",
     "redis": "redis",
     "headscale": "tailscale",
+    "coder": "coder",
 }
 
 ROOT = Path(__file__).resolve().parent.parent