feat(ekonomi): refactor umkm module with sales delete, stock validation, and ordering system

.claude/DATABASE.md

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+# Database & Data Layer
+
+## Prisma Schema
+- Schema at `prisma/schema.prisma` (~2400 lines, 100+ models)
+- Common model conventions: `@default(cuid())` IDs, `createdAt`/`updatedAt` timestamps, `deletedAt DateTime?` (soft delete), `isActive Boolean @default(true)`
+- Seeders per-module in `prisma/_seeder_list/`, orchestrated by `prisma/seed.ts`
+
+## Authentication Flow
+1. User submits phone → OTP sent (email/SMS)
+2. OTP validated → JWT created + iron-session stored
+3. `UserSession` model tracks active sessions
+4. `src/middleware.ts` validates on each request
+5. `src/lib/api-auth.ts` handles JWT/session checks in API routes
+
+## File Handling
+All uploaded files reference the `FileStorage` Prisma model. Uploads land in `WIBU_UPLOAD_DIR` (default: `uploads/`). Seafile is the external storage fallback.