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/useCodexTomlValidation.ts

@@ -1,12 +1,12 @@
-import { useState, useCallback, useEffect, useRef } from 'react';
-import TOML from 'smol-toml';
+import { useState, useCallback, useEffect, useRef } from "react";
+import TOML from "smol-toml";
 
 /**
  * Codex config.toml 格式校验 Hook
  * 使用 smol-toml 进行实时 TOML 语法校验（带 debounce）
  */
 export function useCodexTomlValidation() {
-  const [configError, setConfigError] = useState('');
+  const [configError, setConfigError] = useState("");
   const debounceTimerRef = useRef<NodeJS.Timeout | null>(null);
 
   /**
@@ -17,18 +17,17 @@ export function useCodexTomlValidation() {
   const validateToml = useCallback((tomlText: string): boolean => {
     // 空字符串视为合法（允许为空）
     if (!tomlText.trim()) {
-      setConfigError('');
+      setConfigError("");
       return true;
     }
 
     try {
       TOML.parse(tomlText);
-      setConfigError('');
+      setConfigError("");
       return true;
     } catch (error) {
-      const errorMessage = error instanceof Error
-        ? error.message
-        : 'TOML 格式错误';
+      const errorMessage =
+        error instanceof Error ? error.message : "TOML 格式错误";
       setConfigError(errorMessage);
       return false;
     }
@@ -38,23 +37,26 @@ export function useCodexTomlValidation() {
    * 带 debounce 的校验函数（500ms 延迟）
    * @param tomlText - 待校验的 TOML 文本
    */
-  const debouncedValidate = useCallback((tomlText: string) => {
-    // 清除之前的定时器
-    if (debounceTimerRef.current) {
-      clearTimeout(debounceTimerRef.current);
-    }
+  const debouncedValidate = useCallback(
+    (tomlText: string) => {
+      // 清除之前的定时器
+      if (debounceTimerRef.current) {
+        clearTimeout(debounceTimerRef.current);
+      }
 
-    // 设置新的定时器
-    debounceTimerRef.current = setTimeout(() => {
-      validateToml(tomlText);
-    }, 500);
-  }, [validateToml]);
+      // 设置新的定时器
+      debounceTimerRef.current = setTimeout(() => {
+        validateToml(tomlText);
+      }, 500);
+    },
+    [validateToml],
+  );
 
   /**
    * 清空错误信息
    */
   const clearError = useCallback(() => {
-    setConfigError('');
+    setConfigError("");
   }, []);
 
   // 清理定时器