fix(config): parse YAML list/dict values in set_config_value

[HouMinXi]

Problem

hermes config set custom_providers '- name: oneapi\n type: openai...' writes the value as a quoted string, not a YAML array. The config file ends up with custom_providers: '[{"name":"oneapi",...}]' (string) instead of proper YAML list structure. Hermes then fails to parse custom_providers as a list.

Root cause

set_config_value in hermes_cli/config.py receives its value as a str from argparse. The existing coercion block (lines 5284-5295) only handles bool/int/float — no YAML parse attempt. Multi-line YAML input stays as a raw string and gets written verbatim to config.yaml.

Fix

After the existing bool/int/float coercion, add a YAML parse fallback:

• If the value contains a newline or starts with -, {, or [ (YAML collection indicators), attempt yaml.safe_load(value).
• If it succeeds and returns a non-str type (list, dict, etc.), use the parsed value.
• If it fails (YAMLError) or returns a str, keep the original coerced value.
• Scalars already coerced to bool/int/float above are unaffected — the isinstance(value, str) guard skips them.

yaml is already imported at the top of config.py (line 330), so no new import needed.

Tests

New file tests/hermes_cli/test_config_set_yaml.py (16 tests):

1. Bug-injection proof — multi-line YAML list stored as list (not str). Verified: removing the fix → 4 tests FAIL; restoring → all pass.
2. Scalar regression — bool/int/float/str/enum coercion unchanged (6 bool params + int + float + plain string + string-typed enum).
3. Single-line dict — {enabled: true, name: test} parses to dict.
4. Single-line list — [alpha, beta, gamma] parses to list.
5. Invalid YAML fallback — value with newline that parses back to str stays str; malformed YAML ({a: 1) raises YAMLError and keeps original string.

All 99 tests pass (16 new + 83 existing test_set_config_value.py).

[teknium1]

Thanks for the fix — the bug is real (hermes config set still stores structured values as quoted strings on main), and this is one of the better-built entries in the class: yaml.safe_load, parsed-plain-strings left alone, real isolated-HERMES_HOME tests.

Closing as a duplicate though: this exact fix class has at least 7 earlier open PRs, starting with #37460 (June 2) and with #59182 matching your list/mapping scope most closely. We'll resolve the cluster through the earliest submissions with credit to all. One note for the record if you iterate elsewhere: the new YAML fallback fires even for string-typed keys, bypassing the _default_value_for_key guard main uses to keep string settings (e.g. approvals.mode) from being coerced — any consolidated fix needs to respect that guard.

Appreciate the contribution!