feat: Object Editor Preview Mode & Mobile Optimizations

Major Enhancements:
- Added Preview/Edit mode toggle to StructuredEditor component
  * Preview mode: Read-only view with full text visibility
  * Edit mode: Full editing capabilities with all controls
  * Toggle positioned below title, responsive on mobile
  * Works in both main ObjectEditor view and nested modals

- Clickable nested data in Preview mode
  * JSON/serialized values are blue and clickable
  * Opens modal directly without switching to Edit mode
  * Hover effects and tooltips for better UX
  * No longer need edit mode just to explore structure

Mobile Responsiveness Improvements:
- Fixed all data load notices in ObjectEditor (URL, Paste, Open tabs)
- Fixed all data load notices in TableEditor (URL, Paste, Open tabs)
- Notices now stack vertically on mobile with proper spacing
- Added break-words for long text, whitespace-nowrap for buttons
- Dark mode colors added for better visibility

Table Editor Fixes:
- Fixed sticky header showing row underneath (top-[-1px])
- Made Export section header mobile responsive
- Updated object modal footer layout:
  * Format info and properties combined on single line
  * Buttons moved to separate row below
  * Changed 'Apply Changes' to 'Save Changes' for consistency

StructuredEditor Improvements:
- Moved overflow-x handling from ObjectEditor to StructuredEditor
- Now works consistently in main view and nested modals
- Long strings scroll horizontally everywhere
- 'Add Property' button hidden in Preview mode
- Improved chevron colors for dark mode visibility

Technical Changes:
- StructuredEditor now manages its own editMode state
- readOnly prop can still be passed from parent if needed
- Proper conditional rendering for all UI elements
- Consistent mobile-first responsive design patterns

package.json

@@ -10,6 +10,7 @@
     "@codemirror/lang-html": "^6.4.9",
     "@codemirror/lang-javascript": "^6.2.4",
     "@codemirror/lang-json": "^6.0.2",
+    "@codemirror/lang-sql": "^6.10.0",
     "@codemirror/search": "^6.5.11",
     "@codemirror/state": "^6.5.2",
     "@codemirror/theme-one-dark": "^6.1.3",