fix(cron): prevent duplicate delivery for isolated jobs with announce mode

Fixes #15692

Problem

When an isolated cron job runs with delivery.mode=announce, the output is delivered twice to the target channel with different content:

1. The isolated agent run delivers via deliverOutboundPayloads (structured content) or runSubagentAnnounceFlow (text-based announce) → Message fix: add @lid format support and allowFrom wildcard handling #1
2. executeJobCore in timer.ts unconditionally calls enqueueSystemEvent + requestHeartbeatNow, which wakes the main agent. The main agent processes the system event, generates its own response, and delivers it → Message Login fails with 'WebSocket Error (socket hang up)' ECONNRESET #2

Result: two messages with different content for a single cron run.

Root Cause

In src/cron/service/timer.ts, executeJobCore() posts a summary to the main agent session after every isolated job, regardless of whether the isolated run already delivered its output:

// Before fix:
if (summaryText && deliveryPlan.requested) {
  state.deps.enqueueSystemEvent(label, { agentId: job.agentId });
  if (job.wakeMode === "now") {
    state.deps.requestHeartbeatNow({ reason: \`cron:\${job.id}\` });
  }
}

Fix

Add a delivered flag to RunCronAgentTurnResult that tracks whether the isolated run already delivered its output. Skip enqueueSystemEvent + requestHeartbeatNow when delivered === true.

Changed files: src/cron/isolated-agent/run.ts, src/cron/service/state.ts, src/cron/service/timer.ts

Testing

• All 128 existing cron tests pass
• Lint + format pass (oxlint + oxfmt)
• TypeScript type-check passes

Greptile Overview

Greptile Summary

This PR adds a delivered flag to the isolated cron job execution result so the cron timer can avoid enqueueing a summary system event (and waking the main agent) when the isolated run has already delivered output to the target channel (via outbound payload delivery or the announce flow).

Concretely:

• src/cron/isolated-agent/run.ts now tracks whether delivery happened and returns it.
• src/cron/service/state.ts extends the runIsolatedAgentJob dep return type to include delivered.
• src/cron/service/timer.ts gates enqueueSystemEvent + requestHeartbeatNow behind !res.delivered to prevent duplicate channel messages for delivery.mode=announce isolated runs.

Overall, the change is narrowly scoped to the cron isolated-run → main-session handoff logic and matches the stated root cause in #15692.

Confidence Score: 5/5

• This PR is safe to merge with minimal risk.
• Changes are small, localized, and type-propagated: delivered is only used to suppress a main-session wakeup when isolated delivery already occurred. The new flag is set only on successful delivery paths (outbound payload delivery or announce success) and is otherwise false/undefined, preserving prior behavior. No other call sites are affected beyond the cron service dependency return type and the single gating condition in the timer.
• No files require special attention

_{Last reviewed commit: a355115}

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