* Fixing mattermost configuration parsing bugs
* fix: add homeassistant to skills_config + platform consistency tests
Follow-up for cherry-picked #3512:
- Add homeassistant to skills_config.py PLATFORMS (was in tools_config
but missing from skills_config)
- Add 3 consistency tests that verify all platforms in tools_config have
matching toolset definitions, gateway includes, and skills_config entries
— prevents this class of bug from recurring
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Co-authored-by: DaneelV3 <dannel@v3rtical.tech>