docs: introduce PR template and two issue templates

[Ziminli]

Summary

This PR introduces standardized GitHub community templates for InfiniCCL, including a structured pull request template and issue templates for bug reports and feature requests.

The goal is to improve contributor experience and ensure that all issues and PRs contain the necessary context for debugging distributed systems, backend behavior, and performance-related changes.

These templates enforce consistency across contributions and reduce back-and-forth during review by ensuring required information (environment, backend, reproduction steps, and test results) is provided upfront.

Changes

• Pull Request Template

  • Added a comprehensive PR template under .github/pull_request_template.md
  • Enforces structured reporting of:
    • Summary and motivation
    • Categorized change descriptions
    • Platform/backend impact tracking
    • Performance impact classification
    • Test results and environment details
    • Full contributor checklist aligned with CONTRIBUTING.md
  • Ensures all PRs follow Conventional Commits and InfiniCCL coding standards

• Bug Report Issue Template

  • Added .github/ISSUE_TEMPLATE/bug_report.yml
  • Structured fields for:
    • bug description
    • reproduction steps
    • expected behavior
    • logs and error output
    • backend selection (OpenMPI / MPICH / etc.)
    • platform selection (CPU / NVIDIA GPU / MLU)
  • Includes optional environment section for reproducibility without enforcing it

• Feature Request Issue Template

  • Added .github/ISSUE_TEMPLATE/feature_request.yml
  • Structured prompts for:
    • problem statement
    • proposed solution
    • alternatives considered
    • feature category (backend, runtime, CI, performance, etc.)
    • expected impact level

Platform and Backend Affected

Platform

• N/A- CPU
• N/A- NVIDIA GPU
• N/A- MetaX GPU
• N/A- Cambricon MLU

Backend

• N/A- OpenMPI
• N/A- MPICH

Repository metadata / workflow change only.

Performance Impact

• No performance impact
• Performance improved
• Performance regression possible

This change only affects GitHub metadata and developer workflow; it does not modify runtime code or execution paths.

Known Issues & Future Work

• Current templates need refinement as new backends and platforms are added.

Test Results

Test Involved Platform

• CPU
• NVIDIA GPU
• MetaX GPU
• Cambricon MLU

Test Involved Backend

• OpenMPI
• MPICH

all_gather.log
all_reduce.log
all_to_all.log
broadcast.log
reduce_scatter.log
send_recv.log

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Checklist

Every contributor must verify every item below before requesting
review. Tick each box only after the check has actually been performed —
do not tick speculatively. If an item truly does not apply, replace the
checkbox with N/A and briefly explain why in an inline comment.

Title, Branch, and Commits

• PR title follows Conventional Commits (e.g. feat: …, fix(nccl): …).
• Branch name follows <type>/xxx-yyyy-zzzz where <type> matches the PR title's Conventional Commits type and words are joined with hyphens (see CONTRIBUTING.md §Branches).
• Each commit message follows Conventional Commits.
• Small PR is a single squashable commit; or, for a large PR, every commit is meaningful, well-formed, and independently reviewable (see CONTRIBUTING.md §Pull Requests).
• No stray merge commits from master — the branch is rebased cleanly on top of the current master.
• No fixup! / squash! / wip commits remain.

Scope and Design

• Changes are minimal — no unrelated modifications were introduced (CONTRIBUTING.md §Code/General).
• No dead code, commented-out blocks, debug prints, printf/std::cout/print(...) left behind, or TODO without an owner and issue link.
• No unrelated formatting churn that would obscure the diff.
• Public API changes (if any) are intentional, documented, and reflected in affected callers/tests.

General Code Hygiene

• The code is self-explanatory; comments were added only where the intent or rationale is non-obvious (CONTRIBUTING.md §Code/General).
• Every modified or added file ends with a single trailing newline (CONTRIBUTING.md §Code/General).
• No trailing whitespace, inconsistent indentation, or mixed formatting styles remain.
• Identifiers referenced in comments or error messages are wrapped in Markdown backticks (e.g. the `AllReduce` implementation) (CONTRIBUTING.md §Code/General).
• All comments and error messages are in English (CONTRIBUTING.md §Code/General).
• Comments and error messages are complete sentences — capitalized first letter, terminal punctuation — unless the language/framework convention says otherwise (CONTRIBUTING.md §Code/General; §Python).

C++ Specific (if C++ files changed)

• N/A- Code follows the Google C++ Style Guide strictly.
• N/A- clang-format (version 16, per .github/workflows/clang-format.yml) has been run against all modified applicable files; the diff is clean.
• N/A- No exceptions are thrown. Error paths use assert with messages that include at least __FILE__, __LINE__, and __func__ (CONTRIBUTING.md §C++).
• N/A- Error and warning message wording follows the LLVM Coding Standards (CONTRIBUTING.md §C++).
• N/A- Constructor initializer list order matches member declaration order (CONTRIBUTING.md §C++).
• N/A- Exactly one blank line between classes, between classes and functions, and between functions (CONTRIBUTING.md §C++).
• N/A- Exactly one blank line between members (functions and variables) within a class (CONTRIBUTING.md §C++).
• N/A- Exactly one blank line before and after the contents of a namespace (CONTRIBUTING.md §C++).

Python Specific (if Python files changed)

• N/A- Code is PEP 8 compliant; ruff check passes cleanly on CI (see .github/workflows/ruff.yml).
• N/A- ruff format --check passes cleanly — if not, run ruff format and commit the result.
• N/A- Comments are complete English sentences, starting with a capital letter and ending with punctuation; Markdown backticks are used for code references (CONTRIBUTING.md §Python).
• N/A- Framework-specific conventions (e.g. lowercase pytest.skip messages without terminal period) are honored where applicable (CONTRIBUTING.md §Python).
• N/A- No blank line between the function signature and the body when there is no docstring or comment (CONTRIBUTING.md §Python).
• N/A- A blank line is present before and after if, for, and similar control-flow statements (CONTRIBUTING.md §Python).
• N/A- A blank line appears before each return, except when it directly follows a control-flow statement (CONTRIBUTING.md §Python).
• N/A- Docstrings (if any) follow PEP 257 (CONTRIBUTING.md §Python).
• N/A- Type hints are added / kept consistent with the surrounding code.

Testing

• All applicable example programs have been built and tested successfully on at least one supported heterogeneous cluster setup.

Build, CI, and Tooling

• N/A- New backends or devices have been added to auto-detection in CMakeLists.txt under if(AUTO_DETECT_DEVICES) or to if(AUTO_DETECT_BACKENDS) if applicable.
• Both CI workflows (clang-format.yml, ruff.yml) are green locally (or expected to be green on CI).

Documentation

• README.md, CONTRIBUTING.md, or inline docs updated when behavior, build flags, or developer workflow changed.
• Any user-visible breaking change is called out explicitly under "Summary" and in the commit/PR title with a ! or BREAKING CHANGE: footer.

Security and Safety

• No secrets, access tokens, internal URLs, customer data, or personal hardware identifiers have been committed.
• Third-party code is license-compatible and attributed.
• No unsafe pointer arithmetic, uninitialized reads, or missing bounds checks were introduced.