Turbo models (#1249)

<!-- This is an auto-generated description by cubic. -->

## Summary by cubic
Adds “Dyad Turbo” models for Pro users and centralizes model/provider
constants. Pro users can pick fast, cost‑effective models directly from
the ModelPicker, with clearer labels and gating.

- **New Features**
- Added Dyad Turbo provider in ModelPicker with Qwen3 Coder and Kimi K2
(Pro only).
- Turbo options are hidden for non‑Pro users; “Pro only” badge shown
where applicable.
- “Smart Auto” label now applies only to the Auto model to avoid
confusion.

- **Refactors**
- Moved all model/provider constants into language_model_constants.ts
and updated imports (helpers, client, thinking utils).

<!-- End of auto-generated description by cubic. -->

src/components/ModelPicker.tsx

@@ -25,6 +25,7 @@ import { LocalModel } from "@/ipc/ipc_types";
 import { useLanguageModelProviders } from "@/hooks/useLanguageModelProviders";
 import { useSettings } from "@/hooks/useSettings";
 import { PriceBadge } from "@/components/PriceBadge";
+import { TURBO_MODELS } from "@/ipc/shared/language_model_constants";
 
 export function ModelPicker() {
   const { settings, updateSettings } = useSettings();
@@ -108,6 +109,13 @@ export function ModelPicker() {
   const autoModels =
     !loading && modelsByProviders && modelsByProviders["auto"]
       ? modelsByProviders["auto"].filter((model) => {
+          if (
+            settings &&
+            !isDyadProEnabled(settings) &&
+            model.apiName === "turbo"
+          ) {
+            return false;
+          }
           if (
             settings &&
             isDyadProEnabled(settings) &&
@@ -144,6 +152,9 @@ export function ModelPicker() {
     const provider = providers?.find((p) => p.id === providerId);
     return !(provider && provider.secondary);
   });
+  if (settings && isDyadProEnabled(settings)) {
+    primaryProviders.unshift(["auto", TURBO_MODELS]);
+  }
   const secondaryProviders = providerEntries.filter(([providerId, models]) => {
     if (models.length === 0) return false;
     const provider = providers?.find((p) => p.id === providerId);
@@ -220,7 +231,7 @@ export function ModelPicker() {
                         <div className="flex justify-between items-start w-full">
                           <span className="flex flex-col items-start">
                             <span>
-                              {isSmartAutoEnabled
+                              {isSmartAutoEnabled && model.apiName === "auto"
                                 ? "Smart Auto"
                                 : model.displayName}
                             </span>
@@ -228,7 +239,7 @@ export function ModelPicker() {
                           <div className="flex items-center gap-1.5">
                             {isSmartAutoEnabled && (
                               <span className="text-[10px] bg-gradient-to-r from-indigo-600 via-indigo-500 to-indigo-600 bg-[length:200%_100%] animate-[shimmer_5s_ease-in-out_infinite] text-white px-1.5 py-0.5 rounded-full font-medium">
-                                Dyad Pro
+                                Pro only
                               </span>
                             )}
                             {model.tag && (
@@ -241,7 +252,7 @@ export function ModelPicker() {
                       </DropdownMenuItem>
                     </TooltipTrigger>
                     <TooltipContent side="right">
-                      {isSmartAutoEnabled ? (
+                      {isSmartAutoEnabled && model.apiName === "auto" ? (
                         <p>
                           <strong>Smart Auto</strong> uses a cheaper model for
                           easier tasks
@@ -274,12 +285,16 @@ export function ModelPicker() {
                 return true;
               });
               const provider = providers?.find((p) => p.id === providerId);
+              const providerDisplayName =
+                provider?.id === "auto"
+                  ? "Dyad Turbo"
+                  : (provider?.name ?? providerId);
               return (
                 <DropdownMenuSub key={providerId}>
                   <DropdownMenuSubTrigger className="w-full font-normal">
                     <div className="flex flex-col items-start w-full">
                       <div className="flex items-center gap-2">
-                        <span>{provider?.name ?? providerId}</span>
+                        <span>{providerDisplayName}</span>
                         {provider?.type === "cloud" &&
                           !provider?.secondary &&
                           isDyadProEnabled(settings) && (
@@ -300,7 +315,7 @@ export function ModelPicker() {
                   </DropdownMenuSubTrigger>
                   <DropdownMenuSubContent className="w-56">
                     <DropdownMenuLabel>
-                      {(provider?.name ?? providerId) + " Models"}
+                      {providerDisplayName + " Models"}
                     </DropdownMenuLabel>
                     <DropdownMenuSeparator />
                     {models.map((model) => (