fix: pass config object directly to PrismaLibSql, drop @libsql/client

PrismaLibSql constructor takes a Config object (with url), not a
pre-created Client instance. Remove the unnecessary createClient call
and the @libsql/client direct dependency.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

package.json

@@ -9,7 +9,6 @@
     "lint": "eslint"
   },
   "dependencies": {
-    "@libsql/client": "^0.14.0",
     "@next-auth/prisma-adapter": "^1.0.7",
     "@prisma/adapter-libsql": "^7.5.0",
     "@prisma/client": "^7.5.0",