feat: allow fallback when oss storage is crash

[fatelei]

Description

fix #670

Type of Change

• Bug fix
• New feature
• Refactor
• Performance improvement
• Other

Essential Checklist

Testing

• I have tested the changes locally and confirmed they work as expected
• I have added unit tests where necessary and they pass successfully

Bug Fix (if applicable)

• I have used GitHub syntax to close the related issue (e.g., Fixes #123 or Closes #123)

Additional Information

Please provide any additional context that would help reviewers understand the changes.

[gemini-code-assist]

Code Review

This pull request implements a fallback OSS storage mechanism and an on-demand local plugin launching system. Key additions include the FallbackOSS wrapper to handle primary storage failures and a middleware-integrated method to launch local plugins when needed. Feedback identifies logic errors in the FallbackOSS implementation regarding object existence, deletion, and listing that could lead to data inconsistency. Additionally, there are significant concerns regarding the synchronous nature of plugin launching within HTTP middleware, which could lead to request timeouts and resource exhaustion, and a recommendation to replace magic strings with constants.