fix: unify dialog layout and fix content padding issues

- Fix negative margin overflow in all dialog content areas
- Standardize dialog structure with flex-col layout
- Add consistent py-4 spacing to all content areas
- Ensure proper spacing between header, content, and footer

Affected components:
- AddProviderDialog, EditProviderDialog
- McpFormModal, McpPanel
- UsageScriptModal
- SettingsDialog

All dialogs now follow unified layout pattern:
- DialogContent: flex flex-col max-h-[90vh]
- Content area: flex-1 overflow-y-auto px-6 py-4
- No negative margins that cause content overflow

src/components/providers/forms/hooks/useCommonConfigSnippet.ts

@@ -51,11 +51,7 @@ export function useCommonConfigSnippet({
   // 初始化时检查通用配置片段（编辑模式）
   useEffect(() => {
     if (initialData) {
-      const configString = JSON.stringify(
-        initialData.settingsConfig,
-        null,
-        2,
-      );
+      const configString = JSON.stringify(initialData.settingsConfig, null, 2);
       const hasCommon = hasCommonConfigSnippet(
         configString,
         commonConfigSnippet,
@@ -168,12 +164,7 @@ export function useCommonConfigSnippet({
         }, 0);
       }
     },
-    [
-      commonConfigSnippet,
-      settingsConfig,
-      useCommonConfig,
-      onConfigChange,
-    ],
+    [commonConfigSnippet, settingsConfig, useCommonConfig, onConfigChange],
   );
 
   // 当配置变化时检查是否包含通用配置（但避免在通过通用配置更新时检查）