docs: community growth plan and v3.0 release checklist

- Y5-01: docs/community-growth-plan.md — 3 growth phases from
  dev preview to 10K nodes, tracking via opt-in analytics
- Y5-04: docs/v3-release-checklist.md — prerequisites, release
  steps (code freeze, ISO builds, checksums), post-release plan

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

docs/v3-release-checklist.md

@@ -0,0 +1,24 @@
+# v3.0 Release Checklist
+
+## Prerequisites
+- [ ] 10,000+ active nodes (Y5-01)
+- [ ] Clean security audit report (Y5-03)
+- [ ] Zero-downtime update mechanism tested (Y5-02)
+- [ ] 30-day soak test passed on 5+ hardware platforms
+- [ ] All Year 2-4 features complete and stable
+
+## Release Steps
+1. Freeze code (no new features)
+2. Run full test suite on all certified hardware
+3. Security audit findings resolved
+4. Update CHANGELOG.md and version numbers
+5. Build ISO for x86_64 and ARM64
+6. Create GitHub release with SHA256 checksums
+7. Publish release announcement
+8. Update documentation site
+9. Tag `v3.0.0` in git
+
+## Post-Release
+- Monitor opt-in telemetry for crash reports
+- 48-hour hotfix window (team on standby)
+- Community announcement on Nostr and forums