refactor: remove required constraints and empty API key fields

- Remove 'required' attribute from Codex auth.json textarea
- Remove conditional 'required' logic from API key input field
- Clean up Codex Official preset by removing null OPENAI_API_KEY entry
- Allow more flexible form validation while maintaining backend checks

src/components/providers/forms/CodexConfigSections.tsx

@@ -35,7 +35,6 @@ export const CodexAuthSection: React.FC<CodexAuthSectionProps> = ({
         onBlur={onBlur}
         placeholder={t("codexConfig.authJsonPlaceholder")}
         rows={6}
-        required
         className="w-full px-3 py-2 border border-border-default  dark:bg-gray-800 dark:text-gray-100 rounded-lg text-sm font-mono focus:outline-none focus:ring-2 focus:ring-blue-500/20 dark:focus:ring-blue-400/20  transition-colors resize-y min-h-[8rem]"
         autoComplete="off"
         autoCorrect="off"

src/components/providers/forms/shared/ApiKeySection.tsx

@@ -48,7 +48,6 @@ export function ApiKeySection({
         label={label}
         value={value}
         onChange={onChange}
-        required={category !== "official"}
         placeholder={
           category === "official"
             ? finalPlaceholder.official

src/config/codexProviderPresets.ts

@@ -62,9 +62,7 @@ export const codexProviderPresets: CodexProviderPreset[] = [
     websiteUrl: "https://chatgpt.com/codex",
     isOfficial: true,
     category: "official",
-    auth: {
-      OPENAI_API_KEY: null,
-    },
+    auth: {},
     config: ``,
     theme: {
       icon: "codex",