feat: add support for specifying content-type with OSS across storage…

[IthacaDream]

Summary

feat: add support for specifying content-type with OSS across storage providers

This feature will be useful for people who want to view files via the browser http or https protocol.

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Checklist

Important

Please review the checklist below before submitting your pull request.

• This change requires a documentation update, included: Dify Document
• I understand that this PR may be closed in case there was no previous discussion or issues. (This doesn't apply to typos!)
• I've added a test for each change that was introduced, and I tried as much as possible to make a single atomic change.
• I've updated the documentation accordingly.
• I ran dev/reformat(backend) and cd web && npx lint-staged(frontend) to appease the lint gods

[Copilot]

Pull Request Overview

This PR adds support for specifying the content type when saving files to various OSS storage providers, allowing browsers to correctly interpret file formats.

• Update storage interface (and mock) method signatures to accept an additional content_type parameter
• Propagate the content_type parameter in all storage implementations and update file service calls accordingly

Reviewed Changes

Copilot reviewed 16 out of 16 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
api/tests/unit_tests/oss/__mock/volcengine_tos.py	Updated mock's put_object signature to include content_type
api/services/file_service.py	Updated calls to storage.save to pass mimetype in upload methods
api/extensions/storage/volcengine_tos_storage.py	Added content_type parameter to save and passed it to client put_object
api/extensions/storage/tencent_cos_storage.py	Forwarded content_type via metadata in put_object call
api/extensions/storage/supabase_storage.py	Updated upload to pass file_options with content_type
api/extensions/storage/oracle_oci_storage.py	Added default content_type to the save method
api/extensions/storage/opendal_storage.py	Included content_type in write call using a default when not provided
api/extensions/storage/huawei_obs_storage.py	Updated putObject to include headers for content_type
api/extensions/storage/google_cloud_storage.py	Passed content_type to blob.upload_from_file
api/extensions/storage/base_storage.py	Updated abstract save signature to include content_type
api/extensions/storage/baidu_obs_storage.py	Forwarded content_type to the client’s put_object call
api/extensions/storage/azure_blob_storage.py	Added metadata with Content-Type during blob upload
api/extensions/storage/aws_s3_storage.py	Set a default content_type and passed it in put_object call
api/extensions/storage/aliyun_oss_storage.py	Updated put_object call to pass headers with content_type
api/extensions/ext_storage.py	Updated wrapper save to forward the content_type parameter
api/core/tools/tool_file_manager.py	Modified storage.save calls to include mimetype in file uploads

Comments suppressed due to low confidence (2)

api/extensions/storage/supabase_storage.py:32

• [nitpick] Consider using consistent casing for the content type header key, for example 'Content-Type', to align with other storage provider implementations.

file_options = {"content-type": content_type} if content_type else None

api/extensions/storage/huawei_obs_storage.py:23

• [nitpick] Verify that the header key for specifying content type matches the expected API format; consider using 'Content-Type' if that aligns with documentation.

headers = {"contentType": content_type} if content_type else None