release: v0.4.0 — CI/CD pipeline + workflow tests

[bradygaster]

What's in this PR

Adds the CI/CD pipeline that was missing from the initial v0.4.0 merge (PR #45):

New Workflows

• squad-ci.yml — Runs tests on every PR to dev/preview/main and on push to dev
• squad-preview.yml — Validates preview branch (tests + no .ai-team/ leaks + version check)
• squad-release.yml — Auto-creates git tag + GitHub Release on push to main (idempotent)

Tests

• 22 new tests in \ est/workflows.test.js\ covering template existence, YAML validity, init/upgrade behavior, trigger configs, and byte-for-byte template matching

Distribution

• All 3 workflows have matching templates in \ emplates/workflows/\ so users get them on init/upgrade

Total test count: 45 (23 existing + 22 new) — all passing

⚠️ When this merges to main, \squad-release.yml\ will automatically create the \�0.4.0\ tag and GitHub Release.