🚀 Feature: add vale Linter for documentation maintenance

[CBID2]

🔖 Feature description

Vale is a syntax-aware linter for prose that can enforce style guides, catch common writing errors, and ensure documentation consistency.

🎤 Why is this feature needed ?

Currently, the DocsGPT documentation (located in /docs) lacks automated quality assurance for writing style, grammar, and consistency. Implementing Vale would:
• Maintain Consistency: Enforce consistent terminology, tone, and formatting across all documentation
• Catch Errors Early: Identify spelling mistakes, grammar issues, and style violations during development
• Improve Contributor Experience: Provide immediate feedback to contributors about documentation standards
• Reduce Review Burden: Automate basic style checks, allowing maintainers to focus on content quality
• Align with Best Practices: Follow industry-standard documentation practices used by major open-source projects (GitLab, Kubernetes, Linode use Vale)

✌️ How do you aim to achieve this?

Implementation Plan:
1. Vale Configuration
• Create .vale.ini configuration file at repository root
• Define documentation styles and rules (starting with Vale’s built-in write-good or Microsoft style)
• Configure to scan the /docs directory and all markdown/MDX files
• Set up custom vocabulary for DocsGPT-specific terminology (e.g., “DocsGPT”, “LLM”, “embeddings”, “Nextra”, “Ollama”)
2. Style Rules
• Grammar and spelling checks
• Consistent terminology (e.g., “API key” vs “API Key” vs “api key”)
• Sentence length and readability metrics
• Passive voice detection
• Code block formatting consistency
3. CI/CD Integration
• Add Vale as a GitHub Action (.github/workflows/vale.yml)
• Configure to run on PRs that modify documentation files
• Set up appropriate warning/error levels
• Optimize to check only changed files for performance

🔄️ Additional Information

Here's more information about it and I wanna do it for Hacktoberfest.

👀 Have you spent some time to check if this feature request has been raised before?

• I checked and didn't find similar issue

Are you willing to submit PR?

Yes I am willing to submit a PR!

[Pranavi125]

Hi maintainers 👋
I’d like to take this issue and integrate the Vale linter for documentation consistency.
I can configure it with a .vale.ini file and test it in the docs pipeline.
Please assign this issue to me if it’s available. Thank you!