fix: add userId to comparison inserts (placeholder 'system' until auth is wired)

src/app/actions/comparison.ts

@@ -32,6 +32,7 @@ export async function createComparison(formData: FormData) {
 
   await db.insert(comparisons).values({
     id,
+    userId: "system",
     title,
     query,
     slug,

src/app/api/compare/route.ts

@@ -54,6 +54,7 @@ export async function POST(request: Request) {
 
   await db.insert(comparisons).values({
     id,
+    userId: "system",
     title,
     query: query || null,
     slug,