Improve GitHub issue and pull request templates

[hwanseoc]

Summary

• replace the free-form bug template with a form containing a duplicate check, area dropdown, and one prefilled report textbox
• add a feature request form containing a duplicate check and one prefilled request textbox
• add a single-textbox PR template with license and pre-commit run checks at the top, an affected-area prompt, and focused description sections
• simplify CodeRabbit configuration, skip automatic draft reviews, enable incremental reviews, and pause after five reviewed commits

Why

The current repository has one Markdown bug template, no feature request or PR template, and vague CodeRabbit path instructions. A sample of the 60 most recent issues and PRs found:

• 2 issues and 3 PRs with empty bodies
• feature and question issues without consistent scope, use-case, or environment details
• only 37 PRs mentioning tests, 2 linking an issue, and 4 mentioning pre-commit
• Fix broken paths in !367, clang-format #374 followed GEMM+RoPE+MXFP8 fusion #367 partly to fix clang-format failures

The new templates provide useful prompts without requiring contributors to complete many separate fields. The CodeRabbit settings now make automatic review timing explicit without maintaining generic path-specific prompts.

API and compatibility impact

None. This changes GitHub contribution forms and review automation only.

Testing

• git diff --check — passed
• parsed both issue forms with PyYAML and checked their structure and required fields — passed
• validated .coderabbit.yaml against CodeRabbit schema v2 — passed
• targeted pre-commit hooks skipped the YAML and Markdown files as expected because the configured hooks target C/C++/CUDA/Python

@coderabbitai ignore