ci: add bug report issue template

Add a template for bug reports in GitHub issues.

Author: eli-labz

.github/ISSUE_TEMPLATE/bug_report.md

@@ -0,0 +1,38 @@
+---
+name: Bug report
+about: Report a bug or unexpected behavior
+title: '[Bug] '
+labels: bug
+assignees: ''
+---
+
+## Describe the Bug
+
+A clear description of what the bug is.
+
+## Steps to Reproduce
+
+1. Run `...`
+2. See error
+
+## Expected Behavior
+
+What you expected to happen.
+
+## Environment
+
+- OS: [e.g., Ubuntu 22.04, macOS 14, Windows 11]
+- GPU: [e.g., H100, RTX 4090, M2 Max]
+- Python version: `python --version`
+- PyTorch version: `python -c "import torch; print(torch.__version__)"`
+- uv version: `uv --version`
+
+## Logs / Error Output
+
+```
+Paste relevant logs here
+```
+
+## Additional Context
+
+Any other context (commit hash, dataset used, etc.).