test(tools): add unit tests for error handling functions

* Implement tests for error functions like errRequiredField, errInvalidField, and errEntityNotFound.
* Ensure proper metadata is returned for various error scenarios.
* Validate error handling in CRM, Files, and other tools.
* Introduce tests for parsing stored file IDs and UUIDs.
* Enhance coverage for helper functions related to project resolution and session management.

internal/auth/middleware.go

@@ -89,21 +89,6 @@ func Middleware(cfg config.AuthConfig, keyring *Keyring, oauthRegistry *OAuthReg
 	}
 }
 
-func extractToken(r *http.Request, headerName string) string {
-	token := strings.TrimSpace(r.Header.Get(headerName))
-	if token != "" {
-		return token
-	}
-
-	authHeader := strings.TrimSpace(r.Header.Get("Authorization"))
-	scheme, credentials, ok := strings.Cut(authHeader, " ")
-	if !ok || !strings.EqualFold(scheme, "Bearer") {
-		return ""
-	}
-
-	return strings.TrimSpace(credentials)
-}
-
 func extractBearer(r *http.Request) string {
 	authHeader := strings.TrimSpace(r.Header.Get("Authorization"))
 	scheme, credentials, ok := strings.Cut(authHeader, " ")

internal/auth/oauth_registry_test.go

@@ -60,7 +60,6 @@ func TestMiddlewareAllowsOAuthBasicAuthAndSetsContext(t *testing.T) {
 	}
 }
 
-
 func TestMiddlewareRejectsOAuthMissingOrInvalidCredentials(t *testing.T) {
 	oauthRegistry, err := NewOAuthRegistry([]config.OAuthClient{{
 		ID:           "oauth-client",