feat: add Open Project modal with project browser, soft delete, and duplicate

Replace the prompt-based project loading with a full modal UI:
- Draggable/resizable panel with overlay and backdrop blur
- Filterable project list with incremental fuzzy matching
- Sortable columns (name, created, updated) with asc/desc toggle
- Duplicate project with auto-rename on name conflict
- Soft delete with trash view, restore, and permanent delete
- Auto-purge trash after 30 days
- Orphan media file cleanup on project open
- Skip folders without valid meta.json in project listing

src/components/common/index.ts

@@ -1,4 +1,5 @@
 export { default as KGDropdown } from './KGDropdown';
 export { default as Playhead } from './Playhead';
 export { default as FileImportModal } from './FileImportModal'; 
-export { default as LoadingOverlay } from './LoadingOverlay';
+export { default as LoadingOverlay } from './LoadingOverlay';
+export { default as OpenProjectModal } from './OpenProjectModal';