[andrew-blue]

Summary

Stop extending overdue task bars to today so overdue tasks always render verbatim ending on their actual dueDate (both at rest and during whole-bar drag previews), while preserving .bar-overdue visual indicators and overdue labels.

Related Issue

Linear: IT-84

Changes

• src/utils/date.ts: Extracted computeBarDayRange so tasks with a startDate always span [startDate, dueDate] inclusive and completed/overdue tasks without a startDate anchor a compact 2-day bar ending on dueDate (clamped cleanly at chartStart).
• src/components/GanttRow.tsx: Replaced inline overdue-to-today stretching with computeBarDayRange, updated barStartBaseDate to anchor completed/overdue tasks without startDate at dueDate, and updated movedPreview so dragging an overdue task keeps its preview bar ending on movedPreview.due.
• src/utils/date.test.ts & e2e/gantt.spec.ts: Added unit tests for computeBarDayRange and Chrome/Firefox Playwright E2E coverage verifying verbatim overdue bar rendering, zero automatic mutations on load, .bar-overdue styling, and DetailPanel overdue readout.

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 (24 files / 372 tests passed, 1 file / 17 Firestore emulator tests skipped)
• npm run test:e2e passes (24/24 across Chrome and Firefox)
• Interactive review/testing completed by subagent reviewer

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: 372 passed, 17 Firestore emulator tests skipped
• npm run test:e2e: 24/24 passed across Chrome and Firefox
• Independent subagent interactive review verified verbatim overdue bar bounds (with and without startDate), outgoing dependency arrow anchor at dueDate, live drag preview bounds, zero automatic mutations, and zero console/page errors in Chromium and Firefox.