🤖 fix: only show 1M context checkbox for supported models (#739)

The 1M context window checkbox was appearing for all Anthropic models
(including Opus) but it's only supported for Claude Sonnet 4 and 4.5.

- Changed `ModelSettings` prop from `provider` to full `model` string
- Now uses `supports1MContext()` to determine checkbox visibility

_Generated with `mux`_

Author: ammar-agent

src/browser/components/ChatInput/index.tsx

@@ -871,7 +871,7 @@ export const ChatInput: React.FC<ChatInputProps> = (props) => {
               </div>
 
               <div className="ml-4 flex items-center" data-component="ModelSettingsGroup">
-                <ModelSettings provider={(preferredModel || "").split(":")[0]} />
+                <ModelSettings model={preferredModel || ""} />
               </div>
 
               {preferredModel && (

src/browser/components/ModelSettings.tsx

@@ -1,12 +1,13 @@
 import React from "react";
 import { useProviderOptions } from "@/browser/hooks/useProviderOptions";
+import { supports1MContext } from "@/common/utils/ai/models";
 import { TooltipWrapper, Tooltip } from "./Tooltip";
 
 interface ModelSettingsProps {
-  provider: string;
+  model: string;
 }
 
-export const ModelSettings: React.FC<ModelSettingsProps> = ({ provider }) => {
+export const ModelSettings: React.FC<ModelSettingsProps> = (props) => {
   const { options, setAnthropicOptions, setOpenAIOptions } = useProviderOptions();
 
   const renderOption = (
@@ -35,7 +36,8 @@ export const ModelSettings: React.FC<ModelSettingsProps> = ({ provider }) => {
     </div>
   );
 
-  if (provider === "anthropic") {
+  // 1M context is only available for specific Anthropic models (Sonnet 4/4.5)
+  if (supports1MContext(props.model)) {
     return renderOption(
       "anthropic-1m",
       "1M",
@@ -45,6 +47,7 @@ export const ModelSettings: React.FC<ModelSettingsProps> = ({ provider }) => {
     );
   }
 
+  const provider = props.model.split(":")[0];
   if (provider === "openai") {
     if (import.meta.env.DEV) {
       return renderOption(