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.

agent/internal/grpc/client.go

@@ -80,7 +80,11 @@ func (c *Client) Register(serverID, preRegToken, hostname, ipAddress, osInfo str
 	return resp.AgentToken, nil
 }
 
-func (c *Client) SyncKeys(serverID, agentToken, version string) ([]string, error) {
+// SyncKeys returns the whole response rather than just the keys: the poll now
+// also carries CollectPackages, and a second RPC purely to learn one boolean
+// would be a message every 30 seconds for a value that changes at most when a
+// licence does.
+func (c *Client) SyncKeys(serverID, agentToken, version string) (*pb.SyncResponse, error) {
 	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
 	defer cancel()
 
@@ -92,7 +96,21 @@ func (c *Client) SyncKeys(serverID, agentToken, version string) ([]string, error
 	if err != nil {
 		return nil, err
 	}
-	return resp.PublicKeys, nil
+	return resp, nil
+}
+
+// ReportPackages sends a package report and returns whether the server wants
+// the full list. Given a longer deadline than the other unary calls because the
+// full body is ~150KB on a slow link.
+func (c *Client) ReportPackages(req *pb.ReportPackagesRequest) (bool, error) {
+	ctx, cancel := context.WithTimeout(context.Background(), 60*time.Second)
+	defer cancel()
+
+	resp, err := c.client.ReportPackages(ctx, req)
+	if err != nil {
+		return false, err
+	}
+	return resp.NeedFull, nil
 }
 
 func (c *Client) UploadGeneratedKey(serverID, agentToken, publicKey, privateKey, label string) (string, error) {