fix(gateway): honor nested gateway.* form for 9 more top-level keys

[pierrenode]

What does this PR do?

load_gateway_config() already accepted both the top-level key and the nested gateway.<key> form (written by hermes config set gateway.<key> ...) for multiplex_profiles, max_concurrent_sessions, streaming, and write_sessions_json — each fixed one at a time as users hit it (most recently #59320 for multiplex_profiles). Nine sibling top-level keys never got the same nested fallback: session_reset, quick_commands, stt, stt_echo_transcripts, group_sessions_per_user, thread_sessions_per_user, reset_triggers, always_log_local, and unauthorized_dm_behavior.

hermes config set gateway.<any-of-these> ... builds exactly this nested shape (hermes_cli/config.py's _set_nested has no schema, so it accepts any dotted path), so a user following the same pattern that legitimately works for gateway.multiplex_profiles/gateway.streaming gets a silent no-op for these nine keys instead — the setting is written to config.yaml, hermes config show may even look right, but the gateway never reads it.

Related Issue

No filed issue — found via pattern analysis of load_gateway_config(): 4 of 13 top-level keys it bridges already had the nested-fallback treatment, applied incrementally as separate bugs over time; the other 9 didn't. General class acknowledged in #34067 (hermes config set accepts unknown paths silently) but that issue is about validating writes, not about closing this specific read-side gap.

Type of Change

• 🐛 Bug fix (config silently ignored — same class as fix(gateway): honor nested gateway.multiplex_profiles in load_gateway_config (#51372 salvage) #59320/fix(gateway): read multiplex_profiles from nested gateway section #51372)

Changes Made

• gateway/config.py: read gateway: {...} into a single gateway_section variable once (consolidating three separate yaml_cfg.get("gateway") calls already in the function), add the same top-level-wins/nested-fallback check for each of the nine keys, mirroring the existing write_sessions_json precedent exactly
• tests/gateway/test_config.py: 10 new regression tests (one per key) + a test_top_level_still_wins_over_nested_gateway_section precedence check (verified: fail without the fix, pass with it — the stt test specifically asserts False, not the class default True, so it can't false-pass)

Note for the reviewer

Because every fallback here is guarded by isinstance(gateway_section, dict), this also makes the streaming fallback tolerate a scalar gateway: block (e.g. gateway: disabled) without crashing — the same crash #40837 (open) targets specifically for streaming. This PR doesn't set out to fix that PR's issue, but the consolidated guard covers it as a side effect; flagging it here rather than leaving it to be found in review.

How to Test

python3.11 -m pytest tests/gateway/test_config.py::TestLoadGatewayConfig -k "nested_gateway_section" -v --override-ini="addopts="

Also re-ran the full file and the multiplex-profile suites to confirm no regressions: tests/gateway/test_config.py (96 passed), tests/gateway/test_multiplex_*.py (63 passed).

Checklist

• Read the Contributing Guide | Conventional Commits | No duplicate PR
• Single logical fix | Tests added | Platform: macOS
• Docs — N/A | Cross-platform — N/A

[teknium1]

Thanks for identifying the inconsistent nested gateway read path. The premise remains valid on current main: gateway/config.py:1021-1102 still bridges these settings only from top-level YAML while selected sibling settings already accept nested forms.

Problems

• gateway/config.py:964 does not fully implement the documented top-level-wins rule: a present session_reset: {} is treated as absent and is replaced by gateway.session_reset. Similarly, gateway/config.py:983 replaces a present non-mapping top-level stt value with gateway.stt. The other additions use key-presence precedence, so these two cases are inconsistent.

Suggested changes

• Fall back to nested session_reset / stt only when their top-level keys are absent, then add precedence tests for those cases.
• Current main's a7f65e3b already added the scalar gateway: guard in this same region; retain that guard when resolving the salvage overlap.

Automated hermes-sweeper review.

[teknium1]

This falls back when session_reset is present but {}, contrary to the stated top-level-wins contract. Consider using top-level key presence to decide fallback, and add a precedence regression for an empty top-level mapping plus a populated nested value.

[teknium1]

A present non-mapping top-level stt is treated as absent and replaced by nested gateway.stt. Gate the nested fallback on key absence if top-level precedence must be unconditional.

[teknium1]

Merged via PR #67982 — your commit was cherry-picked onto current main with your authorship preserved in git log (rebase-merge). We added one follow-up commit on top switching the session_reset/stt fallbacks to key-presence precedence (the two inconsistencies flagged in the sweeper review) plus precedence regression tests. Thanks for the thorough fix and the test coverage!