Remove Prisma from project

- Remove @prisma/client and prisma dependencies
- Delete prisma schema and database files
- Remove database context from tRPC
- Clean up Prisma-related scripts and environment variables
- Update README to remove Prisma reference

The project no longer requires a database and builds successfully.

prisma/schema.prisma

@@ -1,12 +0,0 @@
-// This is your Prisma schema file,
-// learn more about it in the docs: https://pris.ly/d/prisma-schema
-
-generator client {
-    provider = "prisma-client-js"
-}
-
-datasource db {
-    provider = "postgresql"
-    url      = env("DATABASE_URL")
-}
-