feat(mcp): add collapsible additional info section in form modal
Improves UX by collapsing optional metadata fields (description, tags, homepage, docs) behind an expandable "Additional Info" section.
Changes:
- Add collapsible section with ChevronUp/ChevronDown icons
- Smart default state: collapsed for new entries, expanded for existing entries with metadata
- Add i18n keys: mcp.form.additionalInfo (zh: "附加信息", en: "Additional Info")
- Keep core fields (ID, name, config) always visible for better focus
Benefits:
- Cleaner, less cluttered form interface
- Users can focus on essential configuration first
- Optional metadata easily accessible when needed