[Prajwal7-2002]

Summary

Implements comprehensive contributor guardrails, fail-proof validation infrastructure, and open-source governance for quantbench (quantbench-engine):

1. Pull Request Template (.github/pull_request_template.md):
   • Enforces precision scheme, bit-packing ratio, and SQNR/perplexity verification.
   • Architectural invariant checklist: scalar/tensor bit-exact roundtripping, pure PyTorch vectorization (zero scalar loops over tensors), >=90% test coverage, and clean conventional commits.
2. Interactive GitHub Issue Forms:
   • .github/ISSUE_TEMPLATE/bug_report.yml: Structured bug reports requiring exact minimal PyTorch reproduction snippet, traceback, and environment diagnostics.
   • .github/ISSUE_TEMPLATE/feature_request.yml: Structured proposals for new sub-byte quantization schemes, calibration methods, or packing runtimes.
   • .github/ISSUE_TEMPLATE/config.yml: Disables blank unformatted issues, pointing users directly to educational guides and security advisories.
3. Security Policy (SECURITY.md):
   • Safe tensor mathematics guidelines and private vulnerability reporting instructions.
4. Code of Conduct (CODE_OF_CONDUCT.md):
   • Contributor Covenant v2.1 professional community standards.
5. Developer Guardrails (.pre-commit-config.yaml):
   • Blocks accidental commits of large weight files (>2MB).
   • Enforces automatic local linting (ruff) and code formatting (ruff-format) before commits.
6. Hardened Cross-Platform CI (.github/workflows/ci.yml):
   • Matrix across Ubuntu, Windows, and macOS on Python 3.11 & 3.12.
   • Strict ruff check, ruff format --check, and pytest suite gates with coverage reporting.