Add TurtleTerm agent reliability status CLI

[mdheller]

Summary

Adds a read-only TurtleTerm local operator surface for SourceOS Agent Reliability evidence.

What changed

• Added assets/sourceos/bin/turtle-agent-status
  • scans local .sourceos evidence artifacts
  • summarizes guardrail decisions, stop-gate artifacts, guarded invocation artifacts, and SocioSphere governance queues
  • reports status as ready, blocked, needs_review, or no_artifacts
  • supports human-readable and JSON output
  • is read-only: no policy, memory, git, queue, or agent mutation
• Added smoke tests to assets/sourceos/tests/test_sourceos_term_smoke.py
  • no-artifacts state
  • blocked guardrail decision
  • pending governance review queue
  • ready state from passing stop-gate/invocation artifacts
• Wired turtle-agent-status into make turtle-smoke Python compilation
• Added turtle-agent-status to Homebrew installed scripts and formula tests
• Updated README command and product-surface docs

Validation

Expected validation:

make turtle-smoke

Linked work

Refs #2
Refs SourceOS Agent Reliability Control Plane workstream.