refactor: move letzshop endpoints to marketplace module and add vendor service tests

Move letzshop-related functionality from tenancy to marketplace module:
- Move admin letzshop routes to marketplace/routes/api/admin_letzshop.py
- Move letzshop schemas to marketplace/schemas/letzshop.py
- Remove letzshop code from tenancy module (admin_vendors, vendor_service)
- Update model exports and imports

Add comprehensive unit tests for vendor services:
- test_company_service.py: Company management operations
- test_platform_service.py: Platform management operations
- test_vendor_domain_service.py: Vendor domain operations
- test_vendor_team_service.py: Vendor team management

Update module definitions:
- billing, messaging, payments: Minor definition updates

Add architecture proposals documentation:
- Module dependency redesign session notes
- Decouple modules implementation plan
- Module decoupling proposal

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

app/modules/marketplace/schemas/__init__.py

@@ -85,6 +85,10 @@ from app.modules.marketplace.schemas.letzshop import (
     LetzshopCachedVendorDetailResponse,
     LetzshopVendorDirectorySyncResponse,
     LetzshopCreateVendorFromCacheResponse,
+    # Product Export
+    LetzshopExportRequest,
+    LetzshopExportFileInfo,
+    LetzshopExportResponse,
 )
 from app.modules.marketplace.schemas.onboarding import (
     # Step status
@@ -184,6 +188,10 @@ __all__ = [
     "LetzshopCachedVendorDetailResponse",
     "LetzshopVendorDirectorySyncResponse",
     "LetzshopCreateVendorFromCacheResponse",
+    # Letzshop - Product Export
+    "LetzshopExportRequest",
+    "LetzshopExportFileInfo",
+    "LetzshopExportResponse",
     # Onboarding - Step status
     "StepStatus",
     "CompanyProfileStepStatus",

app/modules/marketplace/schemas/letzshop.py

@@ -624,3 +624,41 @@ class LetzshopCreateVendorFromCacheResponse(BaseModel):
     message: str
     vendor: dict[str, Any] | None = None
     letzshop_vendor_slug: str
+
+
+# ============================================================================
+# Product Export Schemas
+# ============================================================================
+
+
+class LetzshopExportRequest(BaseModel):
+    """Request body for Letzshop export to pickup folder."""
+
+    include_inactive: bool = Field(
+        default=False,
+        description="Include inactive products in export"
+    )
+
+
+class LetzshopExportFileInfo(BaseModel):
+    """Info about an exported file."""
+
+    language: str
+    filename: str | None = None
+    path: str | None = None
+    size_bytes: int | None = None
+    error: str | None = None
+
+
+class LetzshopExportResponse(BaseModel):
+    """Response from Letzshop export to folder."""
+
+    success: bool
+    message: str
+    vendor_code: str
+    export_directory: str
+    files: list[LetzshopExportFileInfo]
+    celery_task_id: str | None = None  # Set when using Celery async export
+    is_async: bool = Field(default=False, serialization_alias="async")  # True when queued via Celery
+
+    model_config = ConfigDict(populate_by_name=True)