feat: add rebuild and restart functionality for agents, including build process and status reporting

pkg/tui/messages.go

@@ -24,5 +24,14 @@ type MsgServerActionDone struct {
 	Errors   []string
 }
 
+// MsgRebuildDone reports the result of a rebuild & restart cycle.
+type MsgRebuildDone struct {
+	BuildOK   bool
+	BuildLog  string // last lines of build output
+	Restarted int    // agents restarted after build
+	Failed    int
+	Errors    []string
+}
+
 // MsgTick triggers a periodic refresh.
 type MsgTick struct{}