security: supply chain hardening for OpenSSF Best Practices

[debugmcpdev]

Summary

• SHA-pin all GitHub Actions across ci.yml and release.yml (29 action references pinned to immutable commit SHAs)
• Add workflow permissions: contents: read top-level for ci.yml, permissions: {} top-level + job-level for release.yml, contents: read for validate-secrets.yml
• Upgrade pnpm/action-setup from v2 (mutable branch ref) to v4 (immutable tag) — no breaking changes since version: is already set explicitly
• Pin CI tool versions: debugpy==1.8.14, dlv@v1.24.2, pip==25.0.1, build==1.2.2, twine==6.1.0, tomlkit==0.13.2
• Add pnpm audit step to CI pipeline (--prod --audit-level=high, continue-on-error initially)
• Add Dependabot for github-actions, npm, and pip ecosystems (weekly Monday schedule)
• Add CodeQL SAST workflow for TypeScript/JavaScript analysis
• Add OpenSSF Scorecard workflow with SARIF upload and publish_results: true
• Add OpenSSF Scorecard badge to README
• Add 80% statement coverage threshold to vitest config
• Create governance documents: SECURITY.md, CODE_OF_CONDUCT.md (Contributor Covenant v2.1), ARCHITECTURE.md, SUPPLY-CHAIN-SECURITY.md
• Update CONTRIBUTING.md to link to CODE_OF_CONDUCT.md
• Branch protection ruleset created (requires PRs, blocks deletion + force push)

Motivation

Harden supply chain security and lay groundwork for OpenSSF Best Practices Passing and Silver badges. Reference: osoji SUPPLY-CHAIN-SECURITY.md

Remaining manual steps (post-merge)

• Register at bestpractices.dev and add badge URL to README
• Configure PyPI OIDC trusted publisher, then replace twine with pypa/gh-action-pypi-publish
• Add required status checks to branch protection ruleset (CI job names)
• Verify npm provenance: npm audit signatures @debugmcp/mcp-debugger

Test plan

• CI workflow passes with SHA-pinned actions and pinned tool versions
• CodeQL workflow runs and reports to Security tab
• Scorecard workflow runs and produces SARIF results
• Dependabot creates its first update PRs within a week
• pnpm audit --prod --audit-level=high runs in CI (continue-on-error)
• Coverage threshold enforced at 80% statements

🤖 Generated with Claude Code

[github-advanced-security]

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

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