feat: Add CD001-MCP FinDrive Repository Coverage Tests (CD001, #27)

[steadhac]

PR #314 — FinDrive Repository Coverage
Add full unit test coverage for the FinDrive FinDriveFileRepository layer.
Tests exercise delete_file, update_file, get_file_count, list_files, cross-namespace
isolation, and FinDriveFile model methods.
 
No bugs expected in the repository layer — all tests currently pass.
 
Tests follow the established pattern with:
 

• Title / Basically question / Steps / Expected Results
   
  📁 Test Files
  tests/unit/mcp/test_findrive_repositories.py
   

TestDeleteFile

Test ID	Title
test_fd_repo_001	delete_file returns True when file found and deleted
test_fd_repo_002	delete_file returns False when file not found

TestUpdateFile

Test ID	Title
test_fd_repo_003	update_file returns None when file not found
test_fd_repo_004	update_file updates filename
test_fd_repo_005	update_file updates content and file_size
test_fd_repo_006	update_file updates both filename and content
test_fd_repo_007	update_file persists to DB

TestGetFileCount

Test ID	Title
test_fd_repo_008	get_file_count returns total across all files
test_fd_repo_009	get_file_count filtered by vendor_id
test_fd_repo_010	get_file_count returns zero when empty

TestListFiles

Test ID	Title
test_fd_repo_011	list_files filters by folder_path
test_fd_repo_012	list_files respects limit
test_fd_repo_013	get_file cross-namespace returns None

TestFinDriveFileModel

Test ID	Title
test_fd_repo_014	FinDriveFile repr includes id and filename
test_fd_repo_015	to_dict with include_content=True includes content_text