fix: normalize local postgres date columns

frontend/src/lib/db/local-postgres-client-core.ts

@@ -128,6 +128,16 @@ function databaseValue(type: string | undefined, value: unknown): unknown {
   return value;
 }
 
+function queryValue(type: string | undefined, value: unknown): unknown {
+  if (type !== "date" || !(value instanceof Date)) return value;
+  // pg parses DATE at local midnight; UTC formatting can shift the calendar day.
+  return [
+    String(value.getFullYear()).padStart(4, "0"),
+    String(value.getMonth() + 1).padStart(2, "0"),
+    String(value.getDate()).padStart(2, "0"),
+  ].join("-");
+}
+
 class LocalPostgresQueryBuilder implements PromiseLike<QueryResult> {
   private selectedColumns: string[] | null = null;
   private mutation: Mutation | null = null;
@@ -411,7 +421,14 @@ class LocalPostgresQueryBuilder implements PromiseLike<QueryResult> {
           }
 
           const result = await client.query(sql, parameters);
-          const rows = result.rows;
+          const rows = result.rows.map((row) =>
+            Object.fromEntries(
+              Object.entries(row).map(([column, value]) => [
+                column,
+                queryValue(types.get(column), value),
+              ]),
+            ),
+          );
           let data: unknown = this.selectedColumns ? rows : null;
           if (this.cardinality !== "many") {
             if (

frontend/tests/database-local-business.test.ts

@@ -183,20 +183,24 @@ test("local PostgreSQL applies the reviewed business schema and serves authentic
       ),
       `SET\n${userId}\nlocal-user@example.com`,
     );
+    fixture.psql(`update public.profiles set birth_date = '1997-08-08' where id = '${userId}'`);
 
     const local = createLocalPostgresDataClient(
       fixture.connectionUrl("app_runtime", "app-runtime-test-password"),
       { id: userId, email: "local-user@example.com" },
     );
     const profile = await local.from("profiles")
-      .select("id,email,credits")
+      .select("id,email,credits,birth_date,created_at")
       .eq("id", userId)
       .single();
     assert.equal(profile.error, null);
-    assert.deepEqual(profile.data, {
+    const { created_at: createdAt, ...profileData } = profile.data as Record<string, unknown>;
+    assert.ok(createdAt instanceof Date);
+    assert.deepEqual(profileData, {
       id: userId,
       email: "local-user@example.com",
       credits: 0,
+      birth_date: "1997-08-08",
     });
     const nonAbandonedProfiles = await local.from("profiles")
       .select("id")