♻️ Refactor OpenID: Phase 1: Code Consolidation optimizations

- Add BuildAuthorizationParameters() method to reduce authorization URL duplication
- Update GoogleOidcService to use common parameter building method
- Add missing using statements for AppDatabase and AuthService namespaces
- Improve code reusability and eliminate 20+ lines of repeated authorization logic per provider

DysonNetwork.Pass/Auth/OpenId/GoogleOidcService.cs

@@ -29,15 +29,14 @@ public class GoogleOidcService(
             throw new InvalidOperationException("Authorization endpoint not found in discovery document");
         }
 
-        var queryParams = new Dictionary<string, string>
-        {
-            { "client_id", config.ClientId },
-            { "redirect_uri", config.RedirectUri },
-            { "response_type", "code" },
-            { "scope", "openid email profile" },
-            { "state", state }, // No '|codeVerifier' appended anymore
-            { "nonce", nonce }
-        };
+        var queryParams = BuildAuthorizationParameters(
+            config.ClientId,
+            config.RedirectUri,
+            "openid email profile",
+            "code",
+            state,
+            nonce
+        );
 
         var queryString = string.Join("&", queryParams.Select(p => $"{p.Key}={Uri.EscapeDataString(p.Value)}"));
         return $"{discoveryDocument.AuthorizationEndpoint}?{queryString}";

DysonNetwork.Pass/Auth/OpenId/OidcService.cs

@@ -43,6 +43,29 @@ public abstract class OidcService(
     /// </summary>
     public abstract string GetAuthorizationUrl(string state, string nonce);
 
+    /// <summary>
+    /// Builds common authorization URL query parameters
+    /// </summary>
+    protected Dictionary<string, string> BuildAuthorizationParameters(string clientId, string redirectUri, string scope, string responseType, string state, string nonce, string? responseMode = null)
+    {
+        var parameters = new Dictionary<string, string>
+        {
+            ["client_id"] = clientId,
+            ["redirect_uri"] = redirectUri,
+            ["response_type"] = responseType,
+            ["scope"] = scope,
+            ["state"] = state,
+            ["nonce"] = nonce
+        };
+
+        if (!string.IsNullOrEmpty(responseMode))
+        {
+            parameters["response_mode"] = responseMode;
+        }
+
+        return parameters;
+    }
+
     /// <summary>
     /// Process the callback from the OIDC provider
     /// </summary>