[theNEXlevel]

Summary

• replace application database access through lib/db.ts with the shared Prisma client
• migrate API, auth, configuration, student, batch, report, attendance, assignment, fee, user, and remarks queries
• remove the obsolete MySQL query helper and mysql2 runtime dependency
• add typed raw-query exceptions only where legacy joins/report SQL or invalid legacy enum data require them
• normalize BigInt values at API response boundaries and validate numeric request IDs

Validation

• pnpm type-check
• pnpm exec jest --runInBand
• pnpm exec next lint (existing Navbar <img> warning only)
• Prisma validation/generation
• live API smoke checks for student data and document/fee endpoints
• OpenSpec validation passed