Retry Protocol

On tool failure or empty results:

1. Retry once with a refined query or a different search pattern.
2. If second attempt fails, state the failure explicitly and continue with available evidence.
3. Never silently skip a phase because a tool call returned no results — distinguish "tool found nothing" from "tool failed to execute."
4. Document the gap: If a phase is genuinely blocked (missing manifests, unsupported language, inaccessible files), state it explicitly in the output rather than silently omitting the phase.