Feature: Import/Export Bookmarks

[couimet]

Summary

Export/import bookmarks to JSON file for backup, sharing, and cross-editor sync (Cursor ↔ VSCode).

Parent Issue

Part of #160 (RangeLink Bookmarks) - Future Enhancement

Blocked By

• Feature: Bookmarks Data Store (globalState) #162 (Bookmarks Data Store)

Commands

• rangelink.exportBookmarks
• rangelink.importBookmarks

Acceptance Criteria

Export

• Opens save file dialog
• Default filename: rangelink-bookmarks.json
• Exports all bookmarks in JSON format
• Success message with file path

Import

• Opens file picker for JSON file
• Validates JSON structure
• Merge strategy options:
  • "Merge" - add imported bookmarks, skip duplicates (by link)
  • "Replace" - clear existing, import all
• Success message with count

Use Cases

1. Cursor ↔ VSCode sync: Cursor may use different storage path; export/import enables manual sync
2. Backup: Save bookmarks before extension updates
3. Team sharing: Share curated bookmarks with teammates

File Format

{
  "version": 1,
  "exportedAt": "2025-01-15T10:30:00Z",
  "bookmarks": [
    {
      "id": "uuid-1",
      "label": "CLAUDE.md Instructions",
      "link": "/Users/.../CLAUDE.md#L94-L129",
      "description": "Coding guidelines",
      "createdAt": "2025-01-10T...",
      "accessCount": 5
    }
  ]
}

Priority

Low - primarily needed for Cursor users (VSCode has Settings Sync)