What does this PR do?

Fixes a CLI crash when a user switches model mid-session and then sends an image attachment as the next turn.

The CLI queues one-shot notes after commands such as /model and /reload-skills so the model sees the updated session state on the next user turn. That path assumed the next message was always a string. Native image attachment routing can instead turn the next message into an OpenAI-style content-parts list, so the CLI crashed while trying to concatenate the note with a list.

This adds a small helper that prepends queued CLI notes to either plain text messages or native multimodal content lists. For content lists, it prefixes the first text part, or inserts a text part before image parts when no text part exists.

Related Issue

No issue filed. Reported on Discord by privacydied.

Type of Change

• 🐛 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

• cli.py: add _prepend_turn_note_to_message() for one-shot CLI notes on string and native multimodal messages.
• cli.py: use the helper for pending model-switch notes and pending skills-reload notes.
• tests/cli/test_cli_image_command.py: add regression coverage for text messages, native image messages with a text part, and image-only content-part lists.

How to Test

1. Start Hermes on one model, then run /model gpt-5.5 --provider openai-codex.
2. Attach or paste an image as the next message.
3. Confirm the CLI does not crash with TypeError: can only concatenate str (not "list") to str and the image turn reaches the model.

Focused local validation:

• scripts/run_tests.sh -j 4 tests/cli/test_cli_image_command.py — 12 passed
• scripts/run_tests.sh -j 4 tests/cli/test_cli_reload_skills.py — 3 passed
• git diff --check -- cli.py tests/cli/test_cli_image_command.py — clean

Checklist

Code

• I've read the Contributing Guide
• My commit messages follow Conventional Commits (fix(scope):, feat(scope):, etc.)
• I searched for existing PRs to make sure this isn't a duplicate
• My PR contains only changes related to this fix/feature (no unrelated commits)
• I've run pytest tests/ -q and all tests pass
• I've added tests for my changes (required for bug fixes, strongly encouraged for features)
• I've tested on my platform: WSL2 / Linux 6.6.87.2

Documentation & Housekeeping

• I've updated relevant documentation (README, docs/, docstrings) — or N/A
• I've updated cli-config.yaml.example if I added/changed config keys — or N/A
• I've updated CONTRIBUTING.md or AGENTS.md if I changed architecture or workflows — or N/A
• I've considered cross-platform impact (Windows, macOS) per the compatibility guide — or N/A
• I've updated tool descriptions/schemas if I changed tool behavior — or N/A

For New Skills

N/A

Screenshots / Logs

Original crash:

TypeError: can only concatenate str (not "list") to str

Crash site was the pending model-switch note prepend path when the next message was a native multimodal content-parts list.