Add remote session loading

internal/app/session_config_path.go

@@ -19,6 +19,22 @@ func resolveSessionConfigPathWithCandidates(flagValue string, candidates []strin
 		return explicit, nil
 	}
 
+	resolved, err := discoverSessionConfigPathWithCandidates(candidates)
+	if err != nil {
+		return "", err
+	}
+	if resolved.Path != "" {
+		return resolved.Path, nil
+	}
+	return "", missingSessionConfigError(resolved.Searched, "")
+}
+
+type sessionConfigDiscovery struct {
+	Path     string
+	Searched []string
+}
+
+func discoverSessionConfigPathWithCandidates(candidates []string) (sessionConfigDiscovery, error) {
 	ordered := make([]string, 0, len(candidates))
 	for _, raw := range candidates {
 		path := strings.TrimSpace(raw)
@@ -31,19 +47,32 @@ func resolveSessionConfigPathWithCandidates(flagValue string, candidates []strin
 			if info.IsDir() {
 				continue
 			}
-			return filepath.Clean(path), nil
+			return sessionConfigDiscovery{Path: filepath.Clean(path), Searched: ordered}, nil
 		}
 		if errors.Is(err, os.ErrNotExist) {
 			continue
 		}
-		return "", fmt.Errorf("check default session config %q: %w", path, err)
+		return sessionConfigDiscovery{}, fmt.Errorf("check default session config %q: %w", path, err)
 	}
 
+	return sessionConfigDiscovery{Searched: ordered}, nil
+}
+
+func missingSessionConfigError(searched []string, remoteDetail string) error {
+	ordered := append([]string(nil), searched...)
 	if len(ordered) == 0 {
-		return "", fmt.Errorf("no session config path provided and no default locations configured")
+		if strings.TrimSpace(remoteDetail) != "" {
+			return fmt.Errorf("no session config path provided and no default locations configured; %s", remoteDetail)
+		}
+		return fmt.Errorf("no session config path provided and no default locations configured")
 	}
-	return "", fmt.Errorf(
-		"no session config path provided and no default session config found; searched: %s; pass --session to use an explicit path",
+	msg := fmt.Sprintf(
+		"no session config path provided and no default session config found; searched: %s",
 		strings.Join(ordered, ", "),
 	)
+	if strings.TrimSpace(remoteDetail) != "" {
+		msg += "; " + strings.TrimSpace(remoteDetail)
+	}
+	msg += "; pass --session to use an explicit path"
+	return fmt.Errorf("%s", msg)
 }