Implement Cloudflare D1 support with Prisma, update scripts, and enhance documentation

prisma/schema.prisma

@@ -1,11 +1,12 @@
 // Database schema, one company = one org, linked to users and CSV config
 generator client {
   provider = "prisma-client-js"
+  previewFeatures = ["driverAdapters"]
 }
 
 datasource db {
   provider = "sqlite"
-  url      = "file:./dev.db"
+  url      = env("DATABASE_URL")
 }
 
 model Company {