feat: implement marketing pages, core QR tools, and SEO infrastructure for QR Master

CLAUDE.md

@@ -227,6 +227,21 @@ openssl rand -base64 32  # NEXTAUTH_SECRET and IP_SALT
 - Image optimization enabled in `next.config.mjs`
 - Prisma connection pooling recommended for production
 
+## Database Change Policy
+
+**IMPORTANT: No Prisma migrations.** All database schema changes (new columns, new enum values, new tables) must be applied via raw SQL commands directly against the running PostgreSQL instance.
+
+Workflow for schema changes:
+1. Write the raw SQL (e.g. `ALTER TABLE`, `ALTER TYPE ... ADD VALUE`)
+2. Run via Docker: `npm run docker:db` then execute SQL, or use `docker-compose exec db psql -U postgres -d qrmaster -c "..."`
+3. Update `prisma/schema.prisma` to match (so Prisma client types stay in sync)
+4. Run `npx prisma generate` to regenerate the client (no `migrate`)
+
+Example — adding an enum value:
+```sql
+ALTER TYPE "ContentType" ADD VALUE 'BARCODE';
+```
+
 ## Common Pitfalls
 
 1. **Database Connection**: If "Can't reach database server", ensure Docker is running (`npm run docker:dev`)