feat(cli): add /editor compose command

[yeyitech]

Summary

• add a CLI-only /editor command with /edit alias for composing multiline prompts in an external editor
• resolve editors from $EDITOR or $VISUAL first, with fallback detection for common blocking editors like code --wait and terminal editors
• queue saved content back into the CLI input loop, treat empty buffers as cancel, and add coverage for alias resolution and editor file round-trips

Testing

• PYTEST_DISABLE_PLUGIN_AUTOLOAD=1 python3 -m pytest -o addopts='' tests/cli/test_cli_editor_command.py tests/hermes_cli/test_commands.py -q
• PYTEST_DISABLE_PLUGIN_AUTOLOAD=1 python3 -m pytest -o addopts='' tests/cli/test_cli_prefix_matching.py tests/cli/test_cli_loading_indicator.py tests/cli/test_cli_status_command.py -q

Closes #7262

[yeyitech]

Thanks. Quick heads-up: this PR currently shows no GitHub checks on my side (gh pr checks reports “no checks reported”). Since this is a fork PR into NousResearch/hermes-agent, could a maintainer please take a quick look at whether the repo's CI needs manual approval or whether Actions for fork PRs aren't triggering here?

[alt-glitch]

Likely duplicate of #7977 (same /editor compose command). Also related to #7263 (original issue) and #7620. Please coordinate with existing PR authors.

[teknium1]

Closing as superseded by #12934.

Triage notes (medium confidence):
External editor functionality already added via Ctrl+G in cli.py:4456 _open_external_editor() (merged PR #12934 'feat(cli): markdown stripping, compact multiline previews, external editor'); no /editor slash command on main but core feature exists.

Thanks for the contribution — the underlying problem this PR addresses has been resolved by the linked PR on current main. If you believe this was closed in error, please comment and we'll reopen.

(Bulk-closed during a CLI PR triage sweep.)