chore(db): finish Prisma cutover to Drizzle Kit tooling

Move CMS SQL to drizzle/migrations, drop prisma packages/schema, wire drizzle-kit scripts, and regenerate schema names from src/db/schema.ts.

Co-authored-by: Cursor <[email protected]>

.gitignore

@@ -5,7 +5,6 @@ node_modules/
 next-env.d.ts
 .env
 *.tsbuildinfo
-# Prisma client is generated by `prisma generate`
 src/generated/
 # Runtime avatar/badge imaging disk cache
 public/cache/