REFACTORED - Replace Prisma with Drizzle ORM

- Add lib/db (schema, postgres.js client, enums, seed, migrations) on Drizzle
- Rewrite all lib and admin action queries from Prisma to Drizzle
- Keep existing table/column names so no data migration is needed
- Preserve signed-cookie admin auth unchanged
- Map unique-violation handling from Prisma P2002 to SQLSTATE 23505
- Swap deps, scripts, Makefile, and Dockerfile from Prisma to Drizzle

app/_admin/media/actions.ts

@@ -1,6 +1,6 @@
 "use server";
 
-import { MediaKind } from "@prisma/client";
+import { eq } from "drizzle-orm";
 import { revalidatePath } from "next/cache";
 import { redirect } from "next/navigation";
 import { isRedirectError } from "next/dist/client/components/redirect-error";
@@ -11,7 +11,9 @@ import { withFlash } from "@/lib/admin-feedback";
 import { countMediaUsageReferences, getMediaAssetById } from "@/lib/media";
 import { createStandaloneMediaAsset, deleteMediaAssetAndFile } from "@/lib/media-service";
 import { isManagedMediaFilePath } from "@/lib/media-storage";
-import { prisma } from "@/lib/prisma";
+import { db } from "@/lib/db";
+import { mediaAsset } from "@/lib/db/schema";
+import { MediaKind } from "@/lib/db/enums";
 
 async function ensureAdmin() {
   if (!(await isAdminAuthenticated())) {
@@ -71,11 +73,7 @@ export async function deleteMediaAssetAction(formData: FormData) {
       redirect(withFlash(getAdminAppPath("/media"), { error: "Datei wird noch verwendet." }));
     }
 
-    await prisma.mediaAsset.delete({
-      where: {
-        id: asset.id,
-      },
-    });
+    await db.delete(mediaAsset).where(eq(mediaAsset.id, asset.id));
 
     if (isManagedMediaFilePath(asset.url)) {
       await deleteMediaAssetAndFile({