fix: Reduce DB calls when saving archived day edits

[AdamJ]

Summary

Minimize the amount of calls to the database during archiving and editing of archived tasks. Simplifies three calls down to one.

Type of Change

• New feature
• Update to existing feature
• Bug fix
• Documentation update
• Other (describe below)

Related Issue

Closes #

Changes Made

• ArchiveEditDialog.tsx: Only include tasks in the update payload when tasks actually changed or the date changed (date shift re-stamps all task times). Currently it always passes tasks, triggering a SELECT + UPSERT even for notes-only edits.
• TimeTrackingContext.tsx: On error, roll back just the one day using the pre-update snapshot instead of re-fetching all archived days from the DB
• handleSaveDay now checks two conditions before including tasks in the update:
  • tasksContentChanged — user explicitly edited, deleted, or added a task
  • dateChanged — the date was moved (which re-stamps every task’s startTime/endTime)

Checklist

Complete all items that apply to your change. Check N/A for items that don't apply.

Documentation

Run sync-docs skill with Claude Code to automatically update relevant files.

• Any notable changes added to the README.md
• CHANGELOG.md updated accordingly
• N/A — no README changes

General

• Branch is up to date with main
• No unrelated files included in this PR
• Tested locally by invoking the npm run test, npm run lint, and npm run build

Notes for Reviewers