feat: add OpenClaw frontmatter fields — triggers, min_openclaw_version

Adds min_openclaw_version (1.8.0) and voice-triggers->triggers rename
to OpenClaw host config. Syncs version to 0.15.6.0.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

hosts/openclaw.ts

@@ -16,7 +16,11 @@ const openclaw: HostConfig = {
     keepFields: ['name', 'description'],
     descriptionLimit: null,
     extraFields: {
-      version: '0.15.2.0',
+      version: '0.15.6.0',
+      min_openclaw_version: '1.8.0',
+    },
+    renameFields: {
+      'voice-triggers': 'triggers',
     },
   },