fix: align usage display across provider cards by always rendering action buttons

Test and ConfigureUsage buttons are now always rendered instead of
conditionally, with a disabled style for providers that don't support
them (e.g. official subscriptions). This ensures consistent button
container width so the usage display aligns uniformly across all cards.

src/components/providers/ProviderActions.tsx

@@ -246,34 +246,37 @@ export function ProviderActions({
           <Copy className="h-4 w-4" />
         </Button>
 
-        {onTest && (
-          <Button
-            size="icon"
-            variant="ghost"
-            onClick={onTest}
-            disabled={isTesting}
-            title={t("modelTest.testProvider", "测试模型")}
-            className={iconButtonClass}
-          >
-            {isTesting ? (
-              <Loader2 className="h-4 w-4 animate-spin" />
-            ) : (
-              <TestTube2 className="h-4 w-4" />
-            )}
-          </Button>
-        )}
+        <Button
+          size="icon"
+          variant="ghost"
+          onClick={onTest || undefined}
+          disabled={isTesting}
+          title={t("modelTest.testProvider", "测试模型")}
+          className={cn(
+            iconButtonClass,
+            !onTest && "opacity-40 cursor-not-allowed text-muted-foreground",
+          )}
+        >
+          {isTesting ? (
+            <Loader2 className="h-4 w-4 animate-spin" />
+          ) : (
+            <TestTube2 className="h-4 w-4" />
+          )}
+        </Button>
 
-        {onConfigureUsage && (
-          <Button
-            size="icon"
-            variant="ghost"
-            onClick={onConfigureUsage}
-            title={t("provider.configureUsage")}
-            className={iconButtonClass}
-          >
-            <BarChart3 className="h-4 w-4" />
-          </Button>
-        )}
+        <Button
+          size="icon"
+          variant="ghost"
+          onClick={onConfigureUsage || undefined}
+          title={t("provider.configureUsage")}
+          className={cn(
+            iconButtonClass,
+            !onConfigureUsage &&
+              "opacity-40 cursor-not-allowed text-muted-foreground",
+          )}
+        >
+          <BarChart3 className="h-4 w-4" />
+        </Button>
 
         {onOpenTerminal && (
           <Button