feat(auth): add superadmin support for OAuth clients

* Introduce Superadmin field in OAuthClient configuration
* Implement IsSuperadmin method in OAuthRegistry
* Update identityAdmin to check superadmin status via OAuthRegistry
* Add tests for OAuthRegistry superadmin functionality

configs/config.example.yaml

@@ -31,6 +31,7 @@ auth:
       - id: "oauth-client"
         client_id: ""
         client_secret: ""
+        superadmin: false
         description: "optional OAuth client credentials"
 
 database:

internal/app/admin_identity.go

@@ -17,13 +17,21 @@ import (
 )
 
 type identityAdmin struct {
-	pool    *pgxpool.Pool
-	keyring *auth.Keyring
-	logger  *slog.Logger
+	pool          *pgxpool.Pool
+	keyring       *auth.Keyring
+	oauthRegistry *auth.OAuthRegistry
+	logger        *slog.Logger
 }
 
-func newIdentityAdmin(pool *pgxpool.Pool, keyring *auth.Keyring, logger *slog.Logger) *identityAdmin {
-	return &identityAdmin{pool: pool, keyring: keyring, logger: logger}
+func newIdentityAdmin(pool *pgxpool.Pool, keyring *auth.Keyring, oauthRegistry *auth.OAuthRegistry, logger *slog.Logger) *identityAdmin {
+	return &identityAdmin{pool: pool, keyring: keyring, oauthRegistry: oauthRegistry, logger: logger}
+}
+
+func (a *identityAdmin) isSuperadmin(keyID string) bool {
+	if a.keyring != nil && a.keyring.IsSuperadmin(keyID) {
+		return true
+	}
+	return a.oauthRegistry != nil && a.oauthRegistry.IsSuperadmin(keyID)
 }
 
 func loadIdentityKeyring(ctx context.Context, pool *pgxpool.Pool, keyring *auth.Keyring) error {
@@ -71,7 +79,7 @@ func (a *identityAdmin) handler() http.Handler {
 	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		if r.Method != http.MethodGet {
 			keyID, ok := auth.KeyIDFromContext(r.Context())
-			if !ok || a.keyring == nil || !a.keyring.IsSuperadmin(keyID) {
+			if !ok || !a.isSuperadmin(keyID) {
 				writeJSON(w, http.StatusForbidden, map[string]string{"error": "superadmin API key required"})
 				return
 			}

internal/app/app.go

@@ -200,7 +200,7 @@ func routes(logger *slog.Logger, cfg *config.Config, info buildinfo.Info, db *st
 	enrichmentRetryer := tools.NewEnrichmentRetryer(context.Background(), db, bgMetadata, cfg.Capture, cfg.AI.Metadata.Timeout, activeProjects, logger)
 	backfillTool := tools.NewBackfillTool(db, bgEmbeddings, activeProjects, logger)
 	adminActions := newAdminActions(backfillTool, enrichmentRetryer, logger)
-	identityAdmin := newIdentityAdmin(db.Pool(), keyring, logger)
+	identityAdmin := newIdentityAdmin(db.Pool(), keyring, oauthRegistry, logger)
 
 	toolSet := mcpserver.ToolSet{
 		Capture:              tools.NewCaptureTool(db, embeddings, cfg.Capture, activeProjects, enrichmentRetryer, backfillTool),

internal/auth/oauth_registry.go

@@ -31,3 +31,18 @@ func (o *OAuthRegistry) Lookup(clientID string, clientSecret string) (string, bo
 	}
 	return "", false
 }
+
+// IsSuperadmin reports whether keyID (as returned by Lookup) belongs to an
+// OAuth client configured with superadmin: true.
+func (o *OAuthRegistry) IsSuperadmin(keyID string) bool {
+	for _, client := range o.clients {
+		id := client.ID
+		if id == "" {
+			id = client.ClientID
+		}
+		if id == keyID {
+			return client.Superadmin
+		}
+	}
+	return false
+}

internal/auth/oauth_registry_test.go

@@ -32,6 +32,26 @@ func TestNewOAuthRegistryAndLookup(t *testing.T) {
 	}
 }
 
+func TestOAuthRegistryIsSuperadmin(t *testing.T) {
+	registry, err := NewOAuthRegistry([]config.OAuthClient{
+		{ID: "oauth-admin", ClientID: "admin-id", ClientSecret: "admin-secret", Superadmin: true},
+		{ID: "oauth-client", ClientID: "client-id", ClientSecret: "client-secret"},
+	})
+	if err != nil {
+		t.Fatalf("NewOAuthRegistry() error = %v", err)
+	}
+
+	if !registry.IsSuperadmin("oauth-admin") {
+		t.Fatal("IsSuperadmin(oauth-admin) = false, want true")
+	}
+	if registry.IsSuperadmin("oauth-client") {
+		t.Fatal("IsSuperadmin(oauth-client) = true, want false")
+	}
+	if registry.IsSuperadmin("unknown") {
+		t.Fatal("IsSuperadmin(unknown) = true, want false")
+	}
+}
+
 func TestMiddlewareAllowsOAuthBasicAuthAndSetsContext(t *testing.T) {
 	oauthRegistry, err := NewOAuthRegistry([]config.OAuthClient{{
 		ID:           "oauth-client",

internal/config/config.go

@@ -66,6 +66,7 @@ type OAuthClient struct {
 	ID           string `yaml:"id"`
 	ClientID     string `yaml:"client_id"`
 	ClientSecret string `yaml:"client_secret"`
+	Superadmin   bool   `yaml:"superadmin"`
 	Description  string `yaml:"description"`
 }