fix(seed): return numeric IDs from media upload helpers

Payload 3 + PostgreSQL rejects string IDs for upload field relationships;
helpers were returning String(doc.id) which caused ValidationError on
every location/post create that referenced an already-existing media record.

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

src/app/api/admin/seed/route.ts

@@ -16,7 +16,7 @@ async function uploadMedia(
   payload: Awaited<ReturnType<typeof getPayload>>,
   filename: string,
   alt: string
-) {
+): Promise<number | null> {
   const filePath = path.join(process.cwd(), 'public/images/figma', filename)
   if (!fs.existsSync(filePath)) return null
   try {
@@ -27,7 +27,7 @@ async function uploadMedia(
       file: { data: buffer, mimetype: getMimeType(filename), name: filename, size: buffer.length },
       overrideAccess: true,
     })
-    return String(doc.id)
+    return doc.id as number
   } catch {
     return null
   }
@@ -39,7 +39,7 @@ async function findOrUploadMedia(
   filename: string,
   localPath: string,
   alt?: string
-): Promise<string | null> {
+): Promise<number | null> {
   try {
     const existing = await payload.find({
       collection: 'media',
@@ -47,7 +47,7 @@ async function findOrUploadMedia(
       limit: 1,
       overrideAccess: true,
     })
-    if (existing.docs.length > 0) return String(existing.docs[0]!.id)
+    if (existing.docs.length > 0) return existing.docs[0]!.id as number
     const fullPath = path.resolve(process.cwd(), localPath)
     if (!fs.existsSync(fullPath)) return null
     const buffer = fs.readFileSync(fullPath)
@@ -57,7 +57,7 @@ async function findOrUploadMedia(
       file: { data: buffer, mimetype: getMimeType(filename), name: filename, size: buffer.length },
       overrideAccess: true,
     })
-    return String(doc.id)
+    return doc.id as number
   } catch {
     return null
   }
@@ -417,7 +417,7 @@ export async function POST(req: NextRequest) {
           },
           gallery: {
             images: galleryMediaIds
-              .filter((id): id is string => !!id)
+              .filter((id): id is number => !!id)
               .map((id, i) => ({ image: id, alt: `Шуміленд фото ${i + 1}` })),
           },
           video: {