feat: implement product search, media library, and vendor customers

- Add full-text product search in ProductService.search_products()
  searching titles, descriptions, SKUs, brands, and GTINs
- Implement complete vendor media library with file uploads,
  thumbnails, folders, and product associations
- Implement vendor customers API with listing, details, orders,
  statistics, and status management
- Add shop search results UI with pagination and add-to-cart
- Add vendor media library UI with drag-drop upload and grid view
- Add database migration for media_files and product_media tables
- Update TODO file with current launch status (~95% complete)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

models/schema/media.py

@@ -46,7 +46,7 @@ class MediaItemResponse(BaseModel):
     alt_text: str | None = None
     description: str | None = None
     folder: str | None = None
-    metadata: dict[str, Any] | None = None
+    extra_metadata: dict[str, Any] | None = None
     created_at: datetime
     updated_at: datetime | None = None
 
@@ -127,7 +127,7 @@ class MediaDetailResponse(BaseModel):
     alt_text: str | None = None
     description: str | None = None
     folder: str | None = None
-    metadata: dict[str, Any] | None = None
+    extra_metadata: dict[str, Any] | None = None
     created_at: datetime | None = None
     updated_at: datetime | None = None
     message: str | None = None
@@ -147,7 +147,7 @@ class MediaMetadataUpdate(BaseModel):
     alt_text: str | None = Field(None, max_length=500)
     description: str | None = None
     folder: str | None = Field(None, max_length=100)
-    metadata: dict[str, Any] | None = None
+    metadata: dict[str, Any] | None = None  # Named 'metadata' in API, stored as 'extra_metadata'
 
 
 # ============================================================================