Complete metadata query EPIC: add upload endpoints, enhance response fields, standardize audit actions (#18, #19, #20, #22)

- Add GET /api/v1/uploads global endpoint with project/package/user/date filters
- Add GET /api/v1/project/{project}/uploads project-level uploads endpoint
- Add has_more field to PaginationMeta for pagination UI
- Add upload_id, content_type, original_name, created_at to UploadResponse
- Standardize audit action names: project.delete, package.delete, tag.delete, artifact.upload
- Add 13 new integration tests for upload query endpoints and response fields
- 130 tests passing

backend/app/schemas.py

@@ -12,6 +12,7 @@ class PaginationMeta(BaseModel):
     limit: int
     total: int
     total_pages: int
+    has_more: bool = False  # True if there are more pages after current page
 
 
 class PaginatedResponse(BaseModel, Generic[T]):
@@ -341,6 +342,11 @@ class UploadResponse(BaseModel):
     format_metadata: Optional[Dict[str, Any]] = None
     deduplicated: bool = False
     ref_count: int = 1  # Current reference count after this upload
+    # Enhanced metadata (Issue #19)
+    upload_id: Optional[UUID] = None  # UUID of the upload record
+    content_type: Optional[str] = None
+    original_name: Optional[str] = None
+    created_at: Optional[datetime] = None
 
 
 # Resumable upload schemas