squad health readiness check command #1605

Scenario

A gh-aw workflow uses Squad for automated PR review. Sometimes squad init partially fails (network timeout on npx, disk full, missing environment variables). The agent job starts but Squad isn't actually ready. The workflow produces confusing errors like "agent charter not found" or "routing table empty" instead of failing fast with a clear diagnosis.

Operators waste time debugging downstream symptoms when the root cause is a broken init.

Proposal

Add squad health CLI command that validates team state:

• ✅ team.md exists and is parseable
• ✅ All agents in casting registry have valid charters
• ✅ Routing table references only known agents
• ✅ State backend (if configured) is reachable
• ✅ Required environment variables are set
• Exit non-zero on any failure, with structured JSON output for CI consumption
• The shared component calls squad health after init and before dispatching work

Value

Fail-fast with clear diagnostics instead of mysterious downstream errors.