fix(gateway): key-presence precedence for quick_commands nested fallback

[sergioperezcheco]

Follow-up to 7354374. That commit established a key-presence precedence contract for load_gateway_config(): a present (even empty/falsy) top-level value must NOT be silently replaced by the nested gateway.* form, and it fixed session_reset and stt to use "key" not in yaml_cfg gating instead of truthiness checks. quick_commands was left on the old qc is None gate, so it's the one remaining sibling that doesn't honor that contract.

Concretely, quick_commands: null at the top level alongside a populated gateway.quick_commands block causes the nested value to leak through, because yaml_cfg.get("quick_commands") returns None for both "absent" and "present-null". The fix switches the gate to "quick_commands" not in yaml_cfg, matching session_reset/stt exactly. The legitimate nested-only path (top-level key genuinely absent) still falls back normally.

I added two regression tests mirroring the session_reset/stt ones: one asserting a present-null top-level blocks the nested fallback, and one sanity check that the nested fallback still fires when the top-level key is absent. I verified the first test fails on the pre-fix code and passes after, and the full tests/gateway/test_config.py suite (132 tests) stays green.

[alt-glitch]

This was generated by AI during triage.

Related: #67982 merged the neighboring nested-config bridge, while this live, focused patch retains a demonstrated quick_commands present-null precedence residual.

[sergioperezcheco]

To clarify against the triage note: #67982 merged the neighboring nested-config bridge, but this PR fixes a separate `quick_commands` present-null precedence edge case that #67982 does not cover. The residual bug (nested key missing → fallback ignored) still reproduces on current main. Happy to add a regression test if that would help confirm the distinct scope.

[teknium1]

Thanks for the focused regression fix. The quick_commands premise is confirmed on current main: gateway/config.py:1312-1317 uses qc is None, so a present quick_commands: null is replaced by the nested value despite the adjacent documented key-presence contract at gateway/config.py:1302-1305.

Problems

• The same contract is still not applied to profile_routes (gateway/config.py:1356-1360) or streaming (gateway/config.py:1376-1382): present null or mistyped top-level values can still fall back to gateway.*.

Suggested changes

• Please apply the presence-based gate and focused regressions to those sibling paths as well, or explicitly document why their different behavior is intentional.

This is an automated hermes-sweeper review.

[sergioperezcheco]

Applied the presence-based gate to the sibling paths: profile_routes and streaming now use "key" not in yaml_cfg instead of the truthiness check, so a present-but-null or mistyped top-level value is honored (stays empty/default) instead of falling back to gateway.*. Added precedence + fallback regression tests for both, mirroring the quick_commands ones — 136 tests pass locally.