MedSchools.ai analytics dev implementation reviewed

What changed\nImplemented and reviewed MedSchools.ai production analytics tracking in dev: first-party analytics events in user_data.analytics_events, Plausible script wiring, admin analytics dashboard rollups, conversion events, and browser Sentry setup. Verified MedSchools.ai Supabase project is ohkdiwblocbrcfrhxeyg.\n\n## Validation\n- Migration exists at apps/medschools-ai/migrations/006_analytics_events.sql and was applied to Supabase.\n- Local dev server at http://127.0.0.1:5174 accepted /api/analytics event.\n- Verified disposable codex_dev_test row inserted into user_data.analytics_events, then deleted test rows.\n- pnpm build passes.\n- svelte-check still fails on existing repo errors (422 errors/98 warnings), but no diagnostics in touched analytics/Sentry files.\n\n## Important caveat\nServer-side Sentry was attempted but backed out because @sentry/sveltekit server integration caused adapter-vercel/@vercel/nft tracing to fail locally with EACCES reading /etc/sudoers. Current pass is browser Sentry only. Server Sentry needs a separate deploy-safe Vercel/Sentry config pass.\n\n## Deployment caveat\nThe worktree is on main, Vercel project is not linked in apps/medschools-ai/.vercel/project.json, and local changes include unrelated/parallel ranking work. Do not blindly push/deploy all current local changes as analytics.