add rule for strenum

[asukaminato0721]

Important

1. Make sure you have read our contribution guidelines
2. Ensure there is an associated issue and you have been assigned to it
3. Use the correct syntax to link this PR: Fixes #<issue number>.

part of #24876

Summary

ref astral-sh/ruff#3867
ref astral-sh/ruff#10713

Screenshots

Before	After
...	...

Checklist

• 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 a new Ruff linting rule (UP042) to enforce the use of StrEnum instead of traditional Enum for string-based enumerations, following Python modernization best practices.

• Adds UP042 rule to enforce StrEnum usage in the codebase

---

_{Tip: Customize your code reviews with copilot-instructions.md. Create the file or learn how to get started.}

[gemini-code-assist]

Summary of Changes

Hello @asukaminato0721, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request enhances the project's code quality standards by integrating a new linting rule. The primary goal is to ensure consistent and correct usage of string enumerations within the API module, leading to more robust and readable code.

Highlights

• New Linting Rule: Introduced the UP042 rule (use StrEnum) to the api/.ruff.toml configuration, ensuring that string-based enums are properly utilized throughout the API codebase.
• Code Consistency: This change promotes better code consistency and type safety by enforcing the use of StrEnum where applicable, aligning with modern Python best practices.

Using Gemini Code Assist

The full guide for Gemini Code Assist can be found on our documentation page, here are some quick tips.

Invoking Gemini

You can request assistance from Gemini at any point in your pull request via creating an issue comment (i.e. comment on the pull request page) using either /gemini <command> or @gemini-code-assist <command>. Below is a summary of the supported commands.

Feature	Command	Description
Code Review	/gemini review	Performs a code review for the current pull request in its current state.
Pull Request Summary	/gemini summary	Provides a summary of the current pull request in its current state.
Comment	@gemini-code-assist	Responds in comments when explicitly tagged, both in issue comments and review comments.
Help	/gemini help	Displays a list of available commands.

Customization

To customize Gemini Code Assist for GitHub experience, repository maintainers can create a configuration file and/or provide a custom code review style guide (such as PEP-8 for Python) by creating and adding files to a .gemini/ folder in the base of the repository. Detailed instructions can be found here.

Limitations & Feedback

Gemini Code Assist may make mistakes. Please leave feedback on any instances where its feedback is incorrect or counter productive. You can react with 👍 and 👎 on @gemini-code-assist comments. If you're interested in giving your feedback about your experience with Gemini Code Assist for Github and other Google products, sign up here.

You can also get AI-powered code generation, chat, as well as code reviews directly in the IDE at no cost with the Gemini Code Assist IDE Extension.

Footnotes

1. Review the Privacy Notices, Generative AI Prohibited Use Policy, Terms of Service, and learn how to configure Gemini Code Assist in GitHub here. Gemini can make mistakes, so double check it and use code with caution. ↩

[gemini-code-assist]

Code Review

This pull request enables the UP042 ruff rule to enforce using StrEnum where applicable. My review points out that this rule might already be enabled by an existing configuration, making this addition redundant. For improved maintainability of the configuration file, I've suggested either removing the redundant rule or, if it's explicitly required (e.g., as a preview rule), relocating it and adding a comment for clarity.