fix(gpg): make signing key setup non-fatal in setup-gpg (#731)

Setting user.signingKey in the container is optional — if it fails,
GPG agent forwarding and the SSH server should still start. This
prevents a bad signing key configuration from tearing down the
entire tunnel.

Author: skevetter

cmd/agent/workspace/setup_gpg.go

@@ -135,10 +135,8 @@ func (cmd *SetupGPGCmd) Run(ctx context.Context, log log.Logger) error {
 
 	if gpgConf.GitKey != "" {
 		log.Debugf("Setup git signing key")
-		err = gitcredentials.SetupGpgGitKey(gpgConf.GitKey)
-		if err != nil {
-			log.Errorf("Setup git signing key: %v", err)
-			return err
+		if err := gitcredentials.SetupGpgGitKey(gpgConf.GitKey); err != nil {
+			log.Warnf("Setup git signing key failed (non-fatal): %v", err)
 		}
 	}