[poisvin]

Summary

Gather #7361 / T01: https://app.gatherai.co/tasks/7361

Technical verification only: documents current task date storage, rendering and write paths, activity timestamp/actor behaviour, and bounded guidance for due-date and history tickets. No production-code, UI, schema or timezone-setting changes.

• Add characterization tests for actual UI, service/listener and HTTP DTO paths.
• Cover same-day/midnight/DST boundaries, picker seed/display differences, backdated completion and recorded-time history.
• Document existing gaps, including inconsistent date conversions, completion paths without timestamps/history, and local read-only DB timezone observations. These are findings, not fixes.
• Recommend date-only due dates and separate occurrence/recording timestamps for future work; preserve stable-assignee-only attention eligibility.

Verification

• Re-ran all new specs before commit: web 14, sales 8, backend 6 tests passed.
• Full local suites during implementation: backend 453, sales 288, frontend 367 tests passed.
• Standard web/backend/sales typechecks passed.
• Web/sales characterization tests also passed with TZ=Pacific/Kiritimati.
• Whitespace checks passed.
• Standalone web spec-project typecheck has existing project-reference errors; not claimed as passing.

Only the three new test files and docs/technical/task-date-semantics-7361.md are included. Existing local planning files and environment configuration are excluded.