perf: strip heavy base64 data at PostgreSQL level using raw SQL

Previous fix stripped data in Node.js AFTER Prisma loaded the full JSON
from PostgreSQL. For 5 entries with PDF attachments, this still meant
25-50MB transferring from DB to Node.js on every page load.

Now uses prisma.\ with nested jsonb_each/jsonb_object_agg to
strip data/fileData/imageUrl strings >1KB inside the database itself.
Heavy base64 never leaves PostgreSQL when lightweight=true.

src/app/api/storage/route.ts

@@ -57,19 +57,67 @@ export async function GET(request: NextRequest) {
       return NextResponse.json({ value: item ? item.value : null });
     } else {
       // Get all items in namespace
+      const result: Record<string, unknown> = {};
+
+      if (lightweight) {
+        // Strip heavy base64 fields AT THE DATABASE LEVEL using raw SQL.
+        // This prevents PostgreSQL from transferring megabytes of base64
+        // data to Node.js — the heavy strings never leave the DB.
+        // Handles: top-level data/fileData/imageUrl + same keys inside array elements.
+        const rows = await prisma.$queryRaw<
+          Array<{ key: string; value: unknown }>
+        >`
+          SELECT key,
+            CASE WHEN jsonb_typeof(value) = 'object' THEN (
+              SELECT COALESCE(jsonb_object_agg(
+                k,
+                CASE
+                  WHEN k IN ('data', 'fileData', 'imageUrl')
+                       AND jsonb_typeof(v) = 'string'
+                       AND length(v #>> '{}') > 1024
+                  THEN '"__stripped__"'::jsonb
+                  WHEN jsonb_typeof(v) = 'array' THEN (
+                    SELECT COALESCE(jsonb_agg(
+                      CASE
+                        WHEN jsonb_typeof(el) = 'object' THEN (
+                          SELECT COALESCE(jsonb_object_agg(
+                            ek,
+                            CASE
+                              WHEN ek IN ('data', 'fileData', 'imageUrl')
+                                   AND jsonb_typeof(ev) = 'string'
+                                   AND length(ev #>> '{}') > 1024
+                              THEN '"__stripped__"'::jsonb
+                              ELSE ev
+                            END
+                          ), '{}'::jsonb) FROM jsonb_each(el) AS ie(ek, ev)
+                        )
+                        ELSE el
+                      END
+                    ), '[]'::jsonb)
+                    FROM jsonb_array_elements(v) AS ae(el)
+                  )
+                  ELSE v
+                END
+              ), '{}'::jsonb)
+              FROM jsonb_each(value) AS oe(k, v)
+            )
+            ELSE value
+            END AS value
+          FROM "KeyValueStore"
+          WHERE namespace = ${namespace}
+        `;
+        for (const row of rows) {
+          result[row.key] = row.value;
+        }
+      } else {
         const items = await prisma.keyValueStore.findMany({
           where: { namespace },
         });
-
-      // Return as a record { [key]: value }
-      const result: Record<string, any> = {};
         for (const item of items) {
-        if (lightweight) {
-          result[item.key] = stripHeavyFields(item.value);
-        } else {
           result[item.key] = item.value;
         }
       }
+
       return NextResponse.json({ items: result });
     }
   } catch (error) {