refactor(opencode): simplify API format selector

- Reduce npm package options from 10 to 4 core API formats (OpenAI, OpenAI Compatible, Anthropic, Google)
- Rename "AI SDK Package" to "API Format" in i18n (zh/en/ja)
- Remove check icon from Select dropdown items for cleaner UI

src/components/providers/forms/OpenCodeFormFields.tsx

@@ -94,7 +94,7 @@ export function OpenCodeFormFields({
       <div className="space-y-2">
         <FormLabel htmlFor="opencode-npm">
           {t("opencode.npmPackage", {
-            defaultValue: "AI SDK Package",
+            defaultValue: "接口格式",
           })}
         </FormLabel>
         <Select value={npm} onValueChange={onNpmChange}>