feat: agent reports installed packages on the hourly loop

SyncKeys now returns the whole response so the poll can carry
CollectPackages; a separate RPC for one boolean would be a message every
30 seconds for a value that changes when a licence does.

The flag is an atomic: the 30s poll writes it, the hourly package loop
reads it, and they are different goroutines.

internal/sync/sync.go

@@ -92,11 +92,18 @@ func Run(ctx context.Context, cfg *config.Config, version string) error {
 }
 
 func poll(client *grpcclient.Client, cfg *config.Config, version string) error {
-	desired, err := client.SyncKeys(cfg.ServerID, cfg.AgentToken, version)
+	resp, err := client.SyncKeys(cfg.ServerID, cfg.AgentToken, version)
 	if err != nil {
 		return fmt.Errorf("SyncKeys: %w", err)
 	}
 
+	// Stored atomically: the hourly package loop reads this from another
+	// goroutine. Absent on the wire decodes as false, so an older server leaves
+	// collection off rather than on.
+	collectPackagesFlag.Store(resp.CollectPackages)
+
+	desired := resp.PublicKeys
+
 	if runtime.GOOS != "linux" {
 		return nil
 	}
@@ -395,6 +402,11 @@ func runUpdateCheck(ctx context.Context, cfg *config.Config) {
 			return
 		}
 		log.Printf("reported %d available OS updates", len(pkgs))
+
+		// Same hourly cadence, same connection. A package set changes on
+		// roughly the schedule available updates do, so this needs no timer of
+		// its own.
+		reportPackages(client, cfg)
 	}
 
 	doCheck()