feat: add cc-connect start/stop controls

Add backend start/stop endpoints and wire cc-connect UI controls to toggle container state with post-action health refresh and clear error handling.

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

dashboard/frontend/src/lib/api.js

@@ -147,6 +147,14 @@ export function getCcConnectHealth() {
   return get("/cc-connect/health");
 }
 
+export function startCcConnect() {
+  return post("/cc-connect/start");
+}
+
+export function stopCcConnect() {
+  return post("/cc-connect/stop");
+}
+
 export function getInfoEngineItems(params = {}) {
   const query = new URLSearchParams();
   if (params.limit !== undefined) query.set("limit", String(params.limit));