[andrew-blue]

Summary

Surface cross-project Linear issue dependencies (blocks / blocked_by) inline on the Gantt chart as reorderable ghost rows with SVG dependency arrows, schedule violation warnings, 1-click project jumping, and toggleable inline editing.

Design Spec

• docs/superpowers/specs/2026-11-12-cross-project-dependencies-design.md

Related Issue

Linear: IT-59

Changes

• src/types.ts: Added optional cross-project metadata (projectId, projectName, isExternal, isUnscheduledExternal) on Task.
• src/api/linear.ts: Expanded Query 2's relatedIssue selection to fetch cross-project issue metadata in the same GraphQL batch (zero extra API round-trips), deduplicated shared external blockers/blocked issues across local tasks, separated unscheduled external tasks, and excluded ignored/canceled/duplicate/same-project nodes.
• src/utils/crossProject.ts: Added mergeTasksWithExternalOrder (places external ghost rows inline right above tasks they block / right below tasks that block them while respecting unified customOrder), filterExternalTasks, and pruneUnlinkedExternalTasks.
• src/utils/tasks.ts: Updated computeDepViolations to detect cross-project schedule conflicts while skipping isUnscheduledExternal tasks.
• src/hooks/useLinearData.ts & src/App.tsx: Added externalTasks / externalUnscheduledTasks, showExternal persistence, allowExternalEdits write mode (read-only by default, reset on project switch), unified reorderTask across local and ghost rows, cross-project reschedule/rescheduleStart/cycleStatus/createRelation/removeRelation with rollback and undo, while keeping StatsRow, FilterBar counts, Header range, and usePlanningHistory baselines scoped to the active project.
• src/components/GanttRow.tsx, src/components/GanttChart.tsx, src/components/DependencyArrows.tsx, src/components/FilterBar.tsx, src/components/DetailPanel.tsx, src/components/detailPanelStore.ts, src/components/Tooltip.tsx:
  • Distinct ghost row/bar styling with clickable project badge (1-click jump via selectProject).
  • Violet dashed SVG arrows for cross-project links (#8b5cf6) and amber dashed arrows (#f97316) for violated dependencies.
  • Cross-project visibility pill and Edit external lock/unlock toggle in FilterBar + DetailPanel cross-project banner and enriched dependency chips (including unscheduled external links and working × removal).
• src/utils/crossProject.test.ts, src/utils/tasks.test.ts, src/api/linear.test.ts, e2e/gantt.spec.ts: Added 11 unit tests and Chrome/Firefox Playwright E2E coverage.

Checklist

• npm run format:check passes
• npm run lint passes (eslint . --max-warnings 0)
• npm run build, VITE_BACKEND=gcp npm run build, and npm run build:server pass
• npm test passes (23 files / 363 tests passed, 1 file / 17 Firestore emulator tests skipped)
• npm run test:e2e passes (20/20 across Chrome and Firefox)
• Interactive review/testing completed by subagent reviewer (found & fixed stale didDragRef.current click lock after dragging & re-locking external bar)

Verification

• npm run format:check: passed
• npm run lint: passed (0 errors, 0 warnings)
• npm run build, VITE_BACKEND=gcp npm run build, npm run build:server: passed
• npm test: 363 passed, 17 Firestore emulator tests skipped
• npm run test:e2e: 20/20 passed across Chrome and Firefox