fix: address cross-target messaging and reasoning-only payload issues

1. run.ts: remove didSendViaMessagingTool guard from incomplete turn
   detection — this boolean is too coarse and blocks cross-target sends
   (e.g. agent posts to slack but should still reply in originating
   channel). Same-origin dedup is handled downstream by
   buildReplyPayloads()/shouldSuppressMessagingToolReplies.

2. agent-runner-execution.ts: exclude isReasoning payloads from
   hasNonErrorContent check — reasoning-only payloads are dropped
   during delivery, so they should not prevent 429/overload error
   surfacing. Also remove didSendViaMessagingTool guard for same
   cross-target reason as run.ts.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/agents/pi-embedded-runner/run.ts

@@ -1615,7 +1615,6 @@ export async function runEmbeddedPiAgent(
             payloads.length === 0 &&
             !aborted &&
             !timedOut &&
-            !attempt.didSendViaMessagingTool &&
             !attempt.clientToolCall &&
             !attempt.yieldDetected &&
             !attempt.didSendDeterministicApprovalPrompt &&

src/auto-reply/reply/agent-runner-execution.ts

@@ -708,9 +708,12 @@ export async function runAgentTurnWithFallback(params: {
   // error payload into runResult so it flows through the normal
   // kind:"success" path — preserving streaming dedup, message_send
   // suppression, and usage/model metadata updates.
-  if (runResult && !runResult.didSendViaMessagingTool) {
+  if (runResult) {
     const hasNonErrorContent = runResult.payloads?.some(
-      (p) => !p.isError && (p.text?.trim() || (p.mediaUrls?.length ?? 0) > 0),
+      (p) =>
+        !p.isError &&
+        !p.isReasoning &&
+        (p.text?.trim() || (p.mediaUrls?.length ?? 0) > 0),
     );
     if (!hasNonErrorContent) {
       const metaErrorMsg = finalEmbeddedError?.message ?? "";