fix: dashboard body parsing for Vercel serverless

fix: dashboard login uses req.body; remove debug code

fix: dashboard login uses req.body parsed by server

debug: add env debug endpoint

fix: read DASHBOARD_PASSWORD at request time

fix: dashboard URL check for Vercel rewrites

fix: move stats to completions handler for shared /tmp access

feat: time range tabs (Today/Week/Month/All) + real-time clock navbar

feat: API key stats, error capture, key states tracking

feat: dashboard with stats, recent requests, console log, login