General: Enable the support-investigator plugin

Adds the plugin to the checked-in enabled-plugins list, alongside the
existing debugbadger/jvm-tools/devtools entries. It backs the support
mail investigation workflow (/support-investigator:investigate).

Author: d4rken

.claude/settings.json

@@ -2,6 +2,7 @@
   "enabledPlugins": {
     "debugbadger@claude-code-cafe": true,
     "jvm-tools@claude-code-cafe": true,
-    "devtools@claude-code-cafe": true
+    "devtools@claude-code-cafe": true,
+    "support-investigator@claude-code-cafe": true
   }
 }