chore(ci): add SonarCloud static analysis

[jbdevprimary]

Summary

PR #50 (closed as superseded — its diff conflicts with the monorepo restructure #105 and predates significant CI/CD evolution: current `release.yml` already does OIDC-based npm/PyPI publishing and multi-target coverage upload that #50's Docker/Codecov/Coveralls mix doesn't match) proposed adding SonarCloud code quality/security analysis. That specific idea is still worth doing as fresh, focused scope against the current CI setup.

Proposed scope (narrower than #50 — just SonarCloud, not a CI rewrite)

• Add `sonar-project.properties` scoped to the current `packages/{agentic,agentic-crew,providers,triage,meshy-content-generator}` + `tooling/*` layout
• Add `.github/workflows/sonarcloud.yml`: checkout with full history (`fetch-depth: 0`), build, run `pnpm nx run-many -t test:coverage --projects=tag:lang:ts` for lcov, run Python coverage via `pytest --cov`, then the SonarSource scan action
• Requires a `SONAR_TOKEN` secret + SonarCloud project setup (external, one-time manual step)
• Do NOT bundle Coveralls/Codecov/Docker changes from feat: add SonarCloud and Coveralls integration #50 — current CI already has its own coverage-artifact and publishing story; keep this PR scoped to SonarCloud only

[jbdevprimary]

Closing as already delivered. .github/workflows/ci.yml on the restructure branch (landing via PR #105) already has a sonarcloud job — full-history checkout, gated on the typescript/python jobs, downloading their ts-coverage/py-coverage artifacts, and running SonarSource/sonarqube-scan-action@v6 per-package for agentic, triage, agentic-crew, and meshy-content-generator (SONAR_TOKEN secret required, same as this issue's proposal). This must have been added independently in the same restructure work that also closed PR #50. Scope satisfied.