Vehicle Maintenance Service Tracker

Never guess which car needs service — by date or by mileage, whichever comes first. Tracks multiple vehicles, estimates current mileage from odometer history, and flags items overdue by either trigger. Real fuel economy (MPG) from consecutive fill-ups, exact cost-per-mile and total cost of ownership, plus registration/insurance/inspection expiry alerts. Zero dependencies, fully offline, JSON export/import. Playwright-verified vs. independent reimplementation. (AI-assisted; verified working.)