#20992: fix(tts): apply TTS processing to agentCommand outbound delivery path

## Summary - The `deliverAgentCommandResult` path (cron announce, `sessions-send`, etc.) bypasses `dispatchReplyFromConfig`, so `[[tts:...]]` directive tags were never stripped and no audio was synthesised for these payloads - Add `maybeApplyTtsToPayload` before outbound delivery so TTS tags are processed regardless of the delivery path - Build `normalizedPayloads` from TTS-processed content so JSON envelope and return value reflect actually-delivered content Split out from #20685 to keep that PR focused on feishu media support. ## Test plan - [ ] Configure a cron/session-send agent with `[[tts:...]]` tags in output - [ ] Verify TTS tags are stripped from delivered text - [ ] Verify audio is synthesised and included as media in the outbound payload - [ ] Verify `--json` output reflects TTS-processed content (not raw directive markup) - [ ] Verify normal inbound reply flow is unaffected (no double processing) 🤖 Generated with [Claude Code](https://claude.com/claude-code) <!-- greptile_comment --> <h3>Greptile Summary</h3> This PR fixes a bug where TTS directive tags (`[[tts:...]]`) were not being processed in the `deliverAgentCommandResult` code path used by cron announce and `sessions-send` commands. The fix applies TTS processing before outbound delivery and ensures JSON output reflects the actually-delivered content. **Key changes:** - Moved the empty payloads check earlier to avoid processing empty arrays - Added `maybeApplyTtsToPayload` call before outbound delivery to process TTS tags for commands that bypass `dispatchReplyFromConfig` - Updated to use TTS-processed payloads for both JSON normalization and actual delivery - Added a follow-up fix to skip TTS synthesis when `deliveryTarget` is unresolved, avoiding unnecessary API calls when delivery will not occur <h3>Confidence Score: 5/5</h3> - This PR is safe to merge with minimal risk - The changes are well-structured and focused on a specific bug fix. The logic correctly applies TTS processing before delivery, the early return for empty payloads is properly handled, and the follow-up fix appropriately guards against unnecessary API calls. The code follows existing patterns and includes clear explanatory comments. - No files require special attention _{Last reviewed commit: 3e34f2d} <!-- greptile_other_comments_section --> _{(4/5) You can add custom instructions or style guidelines for the agent [here](https://app.greptile.com/review/github)!} <!-- /greptile_comment -->