…ption (NousResearch#42090)

## What does this PR do?

The voice-during-active-run feature (NousResearch#41984) changed
`_enrich_message_with_transcription` so that it returns a
`(enriched_text, successful_transcripts)` tuple instead of a bare string,
which lets callers echo the raw transcript back to the user. The signature
and every other return path were updated to match, but one branch was
missed: when a successfully transcribed clip arrives with the Discord
"empty content" placeholder as its caption, the method still returned the
prefix string on its own. All four call sites unpack the result with
`text, transcripts = await self._enrich_message_with_transcription(...)`,
so that path raised `ValueError: too many values to unpack (expected 2)`
and the inbound voice message was dropped instead of reaching the agent.

This is a real user-facing path rather than a corner case: a Discord voice
note sent without a caption is delivered as exactly that placeholder, so a
captionless voice message that transcribed correctly would crash the
handler precisely when transcription had worked. The fix returns the
proper tuple from that branch so the placeholder is still stripped while
the transcripts continue to flow back to the caller for the echo.

## Related Issue

N/A

## Type of Change

- [x] 🐛 Bug fix (non-breaking change that fixes an issue)
- [ ] ✨ New feature (non-breaking change that adds functionality)
- [ ] 🔒 Security fix
- [ ] 📝 Documentation update
- [ ] ✅ Tests (adding or improving test coverage)
- [ ] ♻️ Refactor (no behavior change)
- [ ] 🎯 New skill (bundled or hub)

## Changes Made

- `gateway/run.py`: in `_enrich_message_with_transcription`, return
  `(prefix, successful_transcripts)` instead of a bare `prefix` from the
  empty-content-placeholder branch, so the contract matches the signature
  and the other return paths.
- `tests/gateway/test_stt_config.py`: add
  `test_enrich_message_with_transcription_returns_tuple_for_empty_content_placeholder`,
  which drives a successful transcription with the placeholder caption and
  asserts the placeholder is stripped while the transcript is still returned.

## How to Test

1. Check out `main` and run the new test — it fails with
   `ValueError: too many values to unpack (expected 2)`, reproducing the
   crash a captionless Discord voice note would trigger.
2. Apply this change and re-run
   `pytest tests/gateway/test_stt_config.py -q` — all tests pass.
3. `ruff check gateway/run.py tests/gateway/test_stt_config.py` and
   `python scripts/check-windows-footguns.py gateway/run.py
   tests/gateway/test_stt_config.py` both pass.

## Checklist

### Code

- [x] I've read the [Contributing Guide](https://github.com/NousResearch/hermes-agent/blob/main/CONTRIBUTING.md)
- [x] My commit messages follow [Conventional Commits](https://www.conventionalcommits.org/) (`fix(scope):`, `feat(scope):`, etc.)
- [x] I searched for [existing PRs](https://github.com/NousResearch/hermes-agent/pulls) to make sure this isn't a duplicate
- [x] My PR contains **only** changes related to this fix/feature (no unrelated commits)
- [x] I've run `pytest tests/ -q` and all tests pass
- [x] I've added tests for my changes (required for bug fixes, strongly encouraged for features)
- [x] I've tested on my platform: macOS 15 (Darwin 25.5)

### Documentation & Housekeeping

- [x] I've updated relevant documentation (README, `docs/`, docstrings) — or N/A
- [x] I've updated `cli-config.yaml.example` if I added/changed config keys — or N/A
- [x] I've updated `CONTRIBUTING.md` or `AGENTS.md` if I changed architecture or workflows — or N/A
- [x] I've considered cross-platform impact (Windows, macOS) per the [compatibility guide](https://github.com/NousResearch/hermes-agent/blob/main/CONTRIBUTING.md#cross-platform-compatibility) — or N/A
- [x] I've updated tool descriptions/schemas if I changed tool behavior — or N/A

…ption (#42090)

## What does this PR do?

The voice-during-active-run feature (#41984) changed
`_enrich_message_with_transcription` so that it returns a
`(enriched_text, successful_transcripts)` tuple instead of a bare string,
which lets callers echo the raw transcript back to the user. The signature
and every other return path were updated to match, but one branch was
missed: when a successfully transcribed clip arrives with the Discord
"empty content" placeholder as its caption, the method still returned the
prefix string on its own. All four call sites unpack the result with
`text, transcripts = await self._enrich_message_with_transcription(...)`,
so that path raised `ValueError: too many values to unpack (expected 2)`
and the inbound voice message was dropped instead of reaching the agent.

This is a real user-facing path rather than a corner case: a Discord voice
note sent without a caption is delivered as exactly that placeholder, so a
captionless voice message that transcribed correctly would crash the
handler precisely when transcription had worked. The fix returns the
proper tuple from that branch so the placeholder is still stripped while
the transcripts continue to flow back to the caller for the echo.

## Related Issue

N/A

## Type of Change

- [x] 🐛 Bug fix (non-breaking change that fixes an issue)
- [ ] ✨ New feature (non-breaking change that adds functionality)
- [ ] 🔒 Security fix
- [ ] 📝 Documentation update
- [ ] ✅ Tests (adding or improving test coverage)
- [ ] ♻️ Refactor (no behavior change)
- [ ] 🎯 New skill (bundled or hub)

## Changes Made

- `gateway/run.py`: in `_enrich_message_with_transcription`, return
  `(prefix, successful_transcripts)` instead of a bare `prefix` from the
  empty-content-placeholder branch, so the contract matches the signature
  and the other return paths.
- `tests/gateway/test_stt_config.py`: add
  `test_enrich_message_with_transcription_returns_tuple_for_empty_content_placeholder`,
  which drives a successful transcription with the placeholder caption and
  asserts the placeholder is stripped while the transcript is still returned.

## How to Test

1. Check out `main` and run the new test — it fails with
   `ValueError: too many values to unpack (expected 2)`, reproducing the
   crash a captionless Discord voice note would trigger.
2. Apply this change and re-run
   `pytest tests/gateway/test_stt_config.py -q` — all tests pass.
3. `ruff check gateway/run.py tests/gateway/test_stt_config.py` and
   `python scripts/check-windows-footguns.py gateway/run.py
   tests/gateway/test_stt_config.py` both pass.

## Checklist

### Code

- [x] I've read the [Contributing Guide](https://github.com/NousResearch/hermes-agent/blob/main/CONTRIBUTING.md)
- [x] My commit messages follow [Conventional Commits](https://www.conventionalcommits.org/) (`fix(scope):`, `feat(scope):`, etc.)
- [x] I searched for [existing PRs](https://github.com/NousResearch/hermes-agent/pulls) to make sure this isn't a duplicate
- [x] My PR contains **only** changes related to this fix/feature (no unrelated commits)
- [x] I've run `pytest tests/ -q` and all tests pass
- [x] I've added tests for my changes (required for bug fixes, strongly encouraged for features)
- [x] I've tested on my platform: macOS 15 (Darwin 25.5)

### Documentation & Housekeeping

- [x] I've updated relevant documentation (README, `docs/`, docstrings) — or N/A
- [x] I've updated `cli-config.yaml.example` if I added/changed config keys — or N/A
- [x] I've updated `CONTRIBUTING.md` or `AGENTS.md` if I changed architecture or workflows — or N/A
- [x] I've considered cross-platform impact (Windows, macOS) per the [compatibility guide](https://github.com/NousResearch/hermes-agent/blob/main/CONTRIBUTING.md#cross-platform-compatibility) — or N/A
- [x] I've updated tool descriptions/schemas if I changed tool behavior — or N/A