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/useModelState.ts

@@ -17,7 +17,10 @@ export function useModelState({
   const [claudeSmallFastModel, setClaudeSmallFastModel] = useState("");
 
   const handleModelChange = useCallback(
-    (field: "ANTHROPIC_MODEL" | "ANTHROPIC_SMALL_FAST_MODEL", value: string) => {
+    (
+      field: "ANTHROPIC_MODEL" | "ANTHROPIC_SMALL_FAST_MODEL",
+      value: string,
+    ) => {
       if (field === "ANTHROPIC_MODEL") {
         setClaudeModel(value);
       } else {