fix: add missing mattermost/matrix/dingtalk toolsets + platform consistency tests (salvage #3512) (#3583)

* 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

---------

Co-authored-by: DaneelV3 <dannel@v3rtical.tech>

toolsets.py

@@ -333,6 +333,24 @@ TOOLSETS = {
         "includes": []
     },
 
+    "hermes-mattermost": {
+        "description": "Mattermost bot toolset - self-hosted team messaging (full access)",
+        "tools": _HERMES_CORE_TOOLS,
+        "includes": []
+    },
+
+    "hermes-matrix": {
+        "description": "Matrix bot toolset - decentralized encrypted messaging (full access)",
+        "tools": _HERMES_CORE_TOOLS,
+        "includes": []
+    },
+
+    "hermes-dingtalk": {
+        "description": "DingTalk bot toolset - enterprise messaging platform (full access)",
+        "tools": _HERMES_CORE_TOOLS,
+        "includes": []
+    },
+
     "hermes-sms": {
         "description": "SMS bot toolset - interact with Hermes via SMS (Twilio)",
         "tools": _HERMES_CORE_TOOLS,
@@ -342,7 +360,7 @@ TOOLSETS = {
     "hermes-gateway": {
         "description": "Gateway toolset - union of all messaging platform tools",
         "tools": [],
-        "includes": ["hermes-telegram", "hermes-discord", "hermes-whatsapp", "hermes-slack", "hermes-signal", "hermes-homeassistant", "hermes-email", "hermes-sms"]
+        "includes": ["hermes-telegram", "hermes-discord", "hermes-whatsapp", "hermes-slack", "hermes-signal", "hermes-homeassistant", "hermes-email", "hermes-sms", "hermes-mattermost", "hermes-matrix", "hermes-dingtalk"]
     }
 }