feat: add issue templates

[danielclough]

Add issue templates and redirect feature requests to Discussions

Summary

This PR adds structured issue templates to help users report bugs more effectively and redirects model/feature requests to GitHub Discussions, reducing noise in the issue tracker.

The current config.yml implicates a new (currently nonexistant) Discussion category called model-requests. Model Requests are so common that it seems that they deserve a Discussion category of their own, but this could be combined into the existing ideas if seperation of concern is not called for.

Motivation

Currently, the issue tracker contains a mix of bug reports, performance questions, build problems, and model requests. This makes it difficult to:

• Triage and prioritize actual bugs
• Track which issues are actionable vs. requests
• Gather consistent information for debugging

Many model requests should be discussions rather than tracked issues, as they represent community wishlists rather than immediate development work.

Changes

Issue Templates Added

1. Bug Report - For reproducible bugs with fields for:

   • Backend (CPU/CUDA/Metal/WGPU)
   • Candle version
   • Platform
   • Minimal reproduction code
   • Error output

2. Performance Issue - For performance problems with fields for:

   • Benchmark code and results
   • PyTorch comparison (if applicable)
   • Hardware specs
   • Feature flags and compilation settings

3. Build/Compilation Failure - For build problems with fields for:

   • Full compilation error
   • Feature flags (CUDA, MKL, Flash Attention, etc.)
   • Cargo.toml dependencies
   • Environment details (Rust/CUDA versions)

4. Incorrect Numerical Output - For correctness bugs with fields for:

   • Expected vs. actual outputs
   • PyTorch comparison
   • Backend-specific behavior
   • Tensor operation context

Redirects

The config.yml redirects the following to Discussions:

• Ideas & Feature Requests → Ideas category
• Model Implementation Request → Model Request category (nonexistant, could be combined into "Ideas")
• Questions & help → Q&A category
• Project showcases → Show and Tell category
• Documentation → Official docs link

Benefits

• Cleaner issue tracker - Only actionable bugs and technical problems
• Better bug reports - Structured templates ensure users provide necessary debugging information
• Improved discoverability - Model requests and questions are easier to find in Discussions
• Reduced maintainer burden - Less time triaging and asking for reproduction steps

Files Changed

.github/ISSUE_TEMPLATE/
├── config.yml
├── bug_report.yml
├── performance_issue.yml
├── build_failure.yml
└── incorrect_output.yml

Motivation

Before: User creates issue "Add xLSTM model support" with just an arxiv link
After: User is redirected to Discussions → Model Implementation Request, where model requests can be discussed and tracked collectively