fix: only count final-phase output as visible for handoff decisions

Progress messages (phase: 'progress') were setting sawVisibleOutput=true,
which blocked failover handoffs when Claude usage was exhausted. Now only
final-phase output counts as visible, allowing reviewer handoff to codex
even after progress messages were shown.

src/message-agent-executor.ts

@@ -534,7 +534,16 @@ export async function runAgentForGroup(
           if (!evaluation.shouldForwardOutput) {
             return;
           }
-          if (typeof outputText === 'string' && outputText.length > 0) {
+          // Only count final-phase output as "visible" for handoff decisions.
+          // Progress messages (phase: 'progress') should not block failover
+          // handoffs — they don't represent meaningful completed work.
+          const isFinalPhase =
+            output.phase === undefined || output.phase === 'final';
+          if (
+            isFinalPhase &&
+            typeof outputText === 'string' &&
+            outputText.length > 0
+          ) {
             streamedState = {
               ...evaluation.state,
               sawVisibleOutput: true,