docs: establish the public roadmap and community lanes - #28

Summary

• publish a concrete 1.0 roadmap, support policy, and documentation community guide
• route questions, bugs, features, documentation reports, and private security reports to the right channels
• make contribution expectations explicit across the README, contributing guide, pull request template, and issue forms

GitHub community state

• enabled Discussions
• created the 1.0 stable milestone
• created four scoped public issues (docs(export): define the versioned trace JSON contract #24–docs: add a troubleshooting guide for unavailable evidence #27), including real good first issue and help wanted work
• added triage and area labels and renamed the unused javascript label to typescript

Validation

• pnpm check
• pnpm docs:build
• GitHub Issue Form YAML parse
• privacy and TypeScript-only scans
• independent review: no findings after the GitHub community state was populated