fix: PR review fixes — restore viewport export, revert schema to PostgreSQL, merge 4 courses, strip content frontmatter

prisma/schema.prisma

@@ -1,10 +1,10 @@
 generator client {
   provider = "prisma-client-js"
-  binaryTargets = ["native", "linux-musl", "debian-openssl-3.0.x", "linux-musl-openssl-3.0.x"]
+  binaryTargets = ["rhel-openssl-3.0.x"]
 }
 
 datasource db {
-  provider = "sqlite"
+  provider = "postgresql"
   url      = env("DATABASE_URL")
 }