Veriloop 0.9.0

Worker completion protocol

• Adds schema-constrained developer and fixer result envelopes.
• Treats host timeout, cancellation, context limits, and tool failures as authoritative fail-closed exits.
• Binds developer checks to the current acceptance batch and fixer checks to Failed findings.
• Rejects mixed prose/JSON fallback responses and permits only one format-only retry.
• Adds deterministic worker exit, contradiction, substitution, and fallback contract coverage.

Both Codex and Claude marketplace manifests now publish version 0.9.0.