What does this PR do?

Fixes gateway/config.py so top-level platform settings under config.yaml are preserved instead of being silently dropped during PlatformConfig.from_dict().

The bug is that load_gateway_config() correctly deep-merges platforms.<name> blocks from config.yaml, but PlatformConfig.from_dict() only kept a fixed allowlist of fields and discarded everything else unless it was nested under extra:. Adapters like webhook and api_server read their settings from config.extra, so shorthand config such as platforms.webhook.port: 9100 never reached the adapter.

This stays narrow at the parser boundary:

• unknown top-level platform keys are folded into extra
• explicit nested extra mappings remain backward compatible and still take precedence on overlap
• invalid non-mapping extra values are ignored with a warning instead of being passed through silently

Related Issue

Fixes #10206

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

• Updated gateway/config.py so PlatformConfig.from_dict() copies unknown top-level platform keys into extra
• Preserved backward compatibility for explicit nested extra values when both shorthand and extra forms are present
• Added a warning when extra is present but not a mapping, so adapters do not silently receive an invalid shape
• Added regression coverage in tests/gateway/test_config.py for:
  • parser-level promotion of unknown top-level keys into extra
  • invalid non-mapping extra values being ignored with a warning
  • load_gateway_config() loading platforms.webhook.host / platforms.webhook.port from config.yaml

How to Test

1. Add this to ~/.hermes/config.yaml:

   platforms:
     webhook:
       enabled: true
       host: 0.0.0.0
       port: 9100

2. Run hermes gateway (or load config through gateway.config.load_gateway_config()).
3. Confirm the webhook adapter now sees host=0.0.0.0 and port=9100 instead of falling back to defaults.
4. Optional validation edge case:

   platforms:
     webhook:
       enabled: true
       extra: not-a-mapping
       port: 9100

   Confirm config loading still preserves port=9100 and logs a warning about the invalid extra value.

Validation

Focused and adjacent checks run locally:

• source /Users/magic/Documents/Code/hermes-agent/venv/bin/activate && python -m pytest tests/gateway/test_config.py -q → 20 passed
• source /Users/magic/Documents/Code/hermes-agent/venv/bin/activate && python -m pytest tests/gateway/test_api_server.py -q → 114 passed
• git diff --check → passed
• source /Users/magic/Documents/Code/hermes-agent/venv/bin/activate && python -m py_compile gateway/config.py tests/gateway/test_config.py → passed

I also ran the repo’s documented broad local test command:

• source /Users/magic/Documents/Code/hermes-agent/venv/bin/activate && python -m pytest tests/ -q --ignore=tests/integration --ignore=tests/e2e --tb=short -n auto

That command is not clean in this checkout: it ended with 98 failed, 11309 passed, 93 skipped, 60 errors, including missing optional dependencies (acp, fastapi, faster_whisper) and unrelated failures in ACP, web server, Discord, Telegram, and other areas outside this patch.

No separate standalone lint command appears in the repo docs, so I did not invent one.

Tested locally on macOS 26.5 with Python 3.11.

Adjacent surfaces checked:

• gateway/platforms/webhook.py reads host / port from config.extra
• gateway/platforms/api_server.py reads host / port from config.extra

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: macOS 26.5

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