feat: native Twitter Bookmark sync via connector framework

[doodlewind]

Summary

• Replace OpenCLI-based Twitter bookmark fetching with a native connector using X's internal GraphQL API, authenticated via Chrome cookie extraction (macOS)
• Introduce a universal connector framework: Connector interface → SyncEngine (dual-frontier) → SyncScheduler (priority queue + lifecycle events + backoff)
• 16 enumerated SyncErrorCode values with user-facing hints for actionable error display
• Live sync progress in SourcesPanel: progress bar, page count, phase indicator

New files

packages/core/src/connectors/
├── types.ts                          -- Connector interface, SyncError, error codes
├── registry.ts                       -- ConnectorRegistry
├── sync-engine.ts                    -- Dual-frontier sync (forward + backfill)
├── sync-scheduler.ts                 -- Priority queue scheduler with backoff
└── twitter-bookmarks/
    ├── index.ts                      -- TwitterBookmarksConnector
    ├── chrome-cookies.ts             -- Chrome cookie extraction (from fieldtheory-cli)
    └── graphql-fetch.ts              -- GraphQL fetch + parse (from fieldtheory-cli)

docs/
├── twitter-bookmark-native.md        -- Original plan
└── connector-sync-architecture.md    -- Architecture doc

Test plan

• Core package type-checks clean, all tests pass
• Twitter auth + fetch verified end-to-end (real Chrome cookies, real API)
• Forward sync paginates correctly (1000+ bookmarks across 50+ pages)
• Incremental sync stops at known items on subsequent runs
• SourcesPanel shows X Bookmarks with real capture count from DB
• Sync progress displays in real-time (page count, new items, progress bar)

Known limitations

• Chrome cookie extraction is macOS-only for now
• Search results are limited to top 20 (pre-existing, not specific to this PR)
• totalSynced in sync state may lag behind actual DB count after crashes (UI reads from DB directly as workaround)

🤖 Generated with Claude Code