chore: remove Sentry integration

Remove @sentry/nextjs and all related files since it was never actively used.
- Delete sentry.server.config.ts, sentry.edge.config.ts
- Delete sentry-example-page and sentry-example-api routes
- Clean up instrumentation.ts, global-error.tsx, middleware.ts
- Remove Sentry env vars from env.example and docs
- Update CLAUDE.md, copilot-instructions.md, PRODUCTION_READINESS.md

Middleware bundle reduced from 86KB to 34.8KB (-51KB).

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

docs/PRODUCTION_READINESS.md

@@ -13,7 +13,7 @@ This document provides an assessment of the portfolio website's production readi
 - [x] Input sanitization on forms
 - [x] SQL injection protection (Prisma ORM)
 - [x] XSS protection via React and sanitize-html
-- [x] Error monitoring with Sentry.io
+- [x] Error logging in development mode
 
 ### Performance
 - [x] Next.js App Router with Server Components
@@ -42,10 +42,8 @@ This document provides an assessment of the portfolio website's production readi
 - [x] Analytics opt-in (Umami - privacy-friendly)
 - [x] Data processing documentation
 - [x] Contact form with consent
-- [x] Sentry.io mentioned in privacy policy
 
 ### Monitoring & Observability
-- [x] Sentry.io error tracking (configured)
 - [x] Umami analytics (self-hosted, privacy-friendly)
 - [x] Health check endpoint (`/api/health`)
 - [x] Logging infrastructure
@@ -79,15 +77,6 @@ This document provides an assessment of the portfolio website's production readi
    - Locations: Hero.tsx, CurrentlyReading.tsx, Projects pages
    - Benefit: Better performance, automatic optimization
 
-2. **Configure Sentry.io DSN**
-   - Set `NEXT_PUBLIC_SENTRY_DSN` in production environment
-   - Set `SENTRY_AUTH_TOKEN` for source map uploads
-   - Get DSN from: https://sentry.io/settings/dk0/projects/portfolio/keys/
-
-3. **Review CSP for Sentry**
-   - May need to adjust Content-Security-Policy headers to allow Sentry
-   - Add `connect-src` directive for `*.sentry.io`
-
 ### Medium Priority
 1. **Accessibility audit**
    - Run Lighthouse audit
@@ -105,7 +94,6 @@ This document provides an assessment of the portfolio website's production readi
 
 ### Low Priority
 1. **Enhanced monitoring**
-   - Custom Sentry contexts for better debugging
    - Performance metrics dashboard
 
 2. **Advanced features**
@@ -123,10 +111,6 @@ Before deploying to production:
    DATABASE_URL=postgresql://...
    REDIS_URL=redis://...
    
-   # Sentry (Recommended)
-   NEXT_PUBLIC_SENTRY_DSN=https://...@sentry.io/...
-   SENTRY_AUTH_TOKEN=...
-   
    # Email (Optional)
    MY_EMAIL=...
    MY_PASSWORD=...
@@ -156,7 +140,6 @@ Before deploying to production:
    - Test HTTPS redirect
 
 6. **Monitoring**
-   - Verify Sentry is receiving events
    - Check Umami analytics tracking
    - Test health endpoint
 
@@ -200,13 +183,12 @@ The application is production-ready with the following notes:
 3. **Performance**: Optimized for production
 4. **SEO**: Properly configured for search engines
 5. **Privacy**: GDPR-compliant with privacy policy
-6. **Monitoring**: Sentry.io configured (needs DSN in production)
+6. **Monitoring**: Umami analytics (self-hosted)
 
 **Next Steps**:
-1. Configure Sentry.io DSN in production environment
-2. Replace `<img>` tags with Next.js `<Image />` for optimal performance
-3. Run final accessibility audit
-4. Monitor performance metrics after deployment
+1. Replace `<img>` tags with Next.js `<Image />` for optimal performance
+2. Run final accessibility audit
+3. Monitor performance metrics after deployment
 
 ---