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/ui/select.tsx

@@ -1,6 +1,6 @@
 import * as React from "react";
 import * as SelectPrimitive from "@radix-ui/react-select";
-import { Check, ChevronDown, ChevronUp } from "lucide-react";
+import { ChevronDown, ChevronUp } from "lucide-react";
 import { cn } from "@/lib/utils";
 
 const Select = SelectPrimitive.Root;
@@ -87,12 +87,6 @@ const SelectItem = React.forwardRef<
     )}
     {...props}
   >
-    <span className="absolute left-2 flex h-3.5 w-3.5 items-center justify-center">
-      <SelectPrimitive.ItemIndicator>
-        <Check className="h-4 w-4" />
-      </SelectPrimitive.ItemIndicator>
-    </span>
-
     <SelectPrimitive.ItemText>{children}</SelectPrimitive.ItemText>
   </SelectPrimitive.Item>
 ));