feat: trigger actual Steam desktop login window via protocol handler for native account addition

frontend/src/hooks/useAccounts.tsx

@@ -38,6 +38,7 @@ interface AccountsContextType {
   updateAccount: (id: string, data: Partial<Account>) => Promise<void>;
   deleteAccount: (id: string) => Promise<void>;
   switchAccount: (loginName: string) => Promise<void>;
+  openSteamAppLogin: () => Promise<void>;
   openSteamLogin: (steamId: string) => Promise<void>;
   shareAccountWithUser: (steamId: string, targetSteamId: string) => Promise<any>;
   revokeAccountAccess: (steamId: string, targetSteamId: string) => Promise<any>;
@@ -127,6 +128,10 @@ export const AccountsProvider: React.FC<{ children: React.ReactNode }> = ({ chil
     await (window as any).electronAPI.switchAccount(loginName);
   };
 
+  const openSteamAppLogin = async () => {
+    await (window as any).electronAPI.openSteamAppLogin();
+  };
+
   const openSteamLogin = async (steamId: string) => {
     await (window as any).electronAPI.openSteamLogin(steamId);
     await syncNow();
@@ -172,7 +177,7 @@ export const AccountsProvider: React.FC<{ children: React.ReactNode }> = ({ chil
   return (
     <AccountsContext.Provider value={{ 
       accounts, serverConfig, isLoading, isSyncing, addAccount, updateAccount, deleteAccount, 
-      switchAccount, openSteamLogin, updateServerConfig, loginToServer, 
+      switchAccount, openSteamAppLogin, openSteamLogin, updateServerConfig, loginToServer, 
       getCommunityAccounts, getServerUsers, shareAccountWithUser, revokeAccountAccess, revokeAllAccountAccess, syncNow, refreshAccounts 
     }}>
       {children}

frontend/src/pages/Dashboard.tsx

@@ -34,7 +34,7 @@ const Dashboard: React.FC = () => {
   const { currentTheme, setTheme } = useAppTheme();
   const { 
     accounts, isLoading, isSyncing, serverConfig, deleteAccount, 
-    switchAccount, openSteamLogin, updateServerConfig, loginToServer, syncNow
+    switchAccount, openSteamAppLogin, openSteamLogin, updateServerConfig, loginToServer, syncNow
   } = useAccounts();
   
   const [searchTerm, setSearchTerm] = useState('');
@@ -104,7 +104,7 @@ const Dashboard: React.FC = () => {
               variant="contained"
               color="primary"
               startIcon={<AddIcon />}
-              onClick={() => openSteamLogin('')}
+              onClick={() => openSteamAppLogin()}
               sx={{ height: 32 }}
             >
               Add