refactor(ekonomi): consolidate Pasar Desa into UMKM module

- Remove "Pasar Desa" as a separate entity; products are now strictly linked to UMKM.
- Delete redundant Pasar Desa API endpoints and state management.
- Update Admin UI: remove "Pasar Desa" menu and unified product management under UMKM.
- Update Public UI: replace "Pasar Desa" with "UMKM" in navbar and unified hub at /darmasaba/ekonomi/umkm.
- Implement mandatory umkmId in PasarDesa model and update seeders accordingly.
- Fix UI bugs, missing imports, and invalid API filters for mandatory umkmId.
- Increment version to 0.1.18.

prisma/schema.prisma

@@ -1434,8 +1434,8 @@ model PasarDesa {
   
   // Data Stok & UMKM
   stok             Int               @default(0)
-  umkm             Umkm?             @relation(fields: [umkmId], references: [id])
-  umkmId           String?
+  umkm             Umkm              @relation(fields: [umkmId], references: [id])
+  umkmId           String
   
   // Relasi Penjualan
   penjualan        PenjualanProduk[]