fix: enhance folder download endpoint with zip file support

[Cristhianzl]

This pull request includes several changes to the src/backend/base/langflow/api/v1/folders.py file to enhance the functionality of the folder download endpoint and various improvements to the codebase. The most important changes include adding new imports, modifying the download_file function to return a zip file, and updating the FlowListReadWithFolderName schema.

Enhancements to folder download functionality:

• src/backend/base/langflow/api/v1/folders.py: Added new imports for handling zip files and JSON encoding, and modified the download_file function to return all flows in a folder as a zip file. [1] [2]

Schema updates:

• src/backend/base/langflow/api/v1/schemas.py: Updated the FlowListReadWithFolderName schema to use Flow instead of FlowRead and renamed the name field to folder_name.

[codspeed-hq[bot]]

CodSpeed Performance Report

Merging #4706 will degrade performances by 36.33%

_{Comparing cz/fix-download-folder (79b8a9c) with main (25a0d76)}

Summary

⚡ 2 improvements ❌ 2 regressions ✅ 11 untouched benchmarks

:warning: Please fix the performance issues or acknowledge them on CodSpeed.

Benchmarks breakdown

	Benchmark	main	cz/fix-download-folder	Change
⚡	test_successful_run_with_input_type_any	297.8 ms	141.9 ms	×2.1
⚡	test_successful_run_with_input_type_text	297 ms	217.7 ms	+36.46%
❌	test_successful_run_with_output_type_any	219.5 ms	246.9 ms	-11.08%
❌	test_successful_run_with_output_type_debug	138.8 ms	218 ms	-36.33%