Add biweekly pay schedule with projected paychecks and dashboard integration
- Add PaySchedule model (anchorDate + amountCents + active flag)
- Add /pay-schedule API route (GET, POST, DELETE)
- Project biweekly pay dates from anchor; deduplicate against manual paychecks
- Merge projected paychecks into dashboard totals and daily chart
- Fix DST day-shift bug in getProjectedPayDates by using Date.UTC throughout
- Rewrite paycheck workspace: schedule panel at top, manual entry below,
projected dates with "Mark received" buttons, confirmed badges
- Pass paySchedule context to Ollama insight prompt
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>