Export time entries as CSV

[grmbyrn]

Problem

Freelancers often need to provide a breakdown of hours to accountants
or clients. There is no way to export time entry data from the app.

Proposed Solution

Add a CSV export button to the time entries view, with optional filters
for date range and client.

Acceptance Criteria

• "Export CSV" button visible on the timer/log page
• Export includes: date, client, project (if set), duration, hourly rate, total
• User can filter by client and date range before exporting
• File downloads with a sensible filename e.g. worklog-export-2026-03.csv

Labels

enhancement