Open-source setup: license, governance docs, CI, and cleanup

[yrks12]

Makes the repo ready for a public open-source release.

Added

• LICENSE — Apache-2.0 (the legally required piece)
• NOTICE, SECURITY.md (recipe trust model + private vuln reporting)
• CONTRIBUTING.md, CODE_OF_CONDUCT.md (Contributor Covenant 2.1)
• CHANGELOG.md (0.1.0)
• CI — .github/workflows/ci.yml: ruff check + pytest on Python 3.10–3.13
• Issue templates (bug / feature) + chooser config, PR template
• examples/hackernews.tools.json — a neutral public-site example recipe

Cleanup

• README: removed the "Generated SDKs" section that referenced private/git-ignored recipes (incl. an internal yairtech site); replaced with a pointer to examples/. Added License + Contributing sections.
• pyproject.toml: declared Apache-2.0 license, classifiers, and project URLs
• Fixed 9 pre-existing ruff errors so CI is green on first run

Verified locally

• ruff check source — clean
• pytest source — 27 passed
• No .env ever committed; no secrets/personal data in tracked files

🤖 Generated with Claude Code