fix: resolve Prisma __dirname ESM error in production Docker build

Move @prisma/client and prisma to dependencies so adapter-node
externalizes them instead of bundling. Add ssr.external config
for Vite to prevent inlining Prisma's CJS engine loader.

package.json

@@ -41,6 +41,8 @@
 		"svelte-i18n": "^4.0.1",
 		"sveltekit-superforms": "^2.22.0",
 		"tailwind-merge": "^2.6.0",
+		"@prisma/client": "^6.2.0",
+		"prisma": "^6.2.0",
 		"zod": "^3.24.0"
 	},
 	"prisma": {
@@ -48,7 +50,6 @@
 	},
 	"devDependencies": {
 		"@eslint/js": "^9.18.0",
-		"@prisma/client": "^6.2.0",
 		"@sveltejs/package": "^2.3.0",
 		"@tailwindcss/vite": "^4.0.0",
 		"@testing-library/svelte": "^5.2.0",
@@ -63,7 +64,6 @@
 		"prettier": "^3.4.0",
 		"prettier-plugin-svelte": "^3.3.0",
 		"prettier-plugin-tailwindcss": "^0.6.0",
-		"prisma": "^6.2.0",
 		"svelte-check": "^4.0.0",
 		"tailwindcss": "^4.0.0",
 		"tsx": "^4.21.0",