New: Message controller client

coscine/issues#2881

.vscode/settings.json

 {
+  "workbench.colorCustomizations": {
+    "activityBar.background": "#678367",
+    "activityBar.foreground": "#dcdcdc",
+    "activityBar.inactiveForeground": "#384238",
+    "activityBar.activeBorder": "#384238",
+    "activityBarBadge.background": "#384238",
+    "activityBarBadge.foreground": "#dcdcdc"
+  },
   "search.exclude": {
     "**/.yarn": true,
     "**/.pnp.*": true
@@ -7,4 +15,4 @@
   "prettier.prettierPath": ".yarn/sdks/prettier/index.cjs",
   "typescript.tsdk": ".yarn/sdks/typescript/lib",
   "typescript.enablePromptUseWorkspaceTsdk": true
-}
+}
\ No newline at end of file