refactor: extract shared ServiceTier type from ServiceTierSchema

The OpenAI service-tier literal union ('auto' | 'default' | 'flex' |
'priority') was duplicated in three places: the CLI options interface
(src/cli/run.ts), the providerModelFactory cast at the providers.jsonc
boundary, and a local OpenAIServiceTier alias in ProvidersSection.tsx.

ServiceTierSchema (src/common/config/schemas/providersConfig.ts)
already defines this enum as the runtime source of truth, so derive a
TypeScript ServiceTier alias via z.infer once and import it at each
site. Pure type-only refactor; the emitted JS and the schema remain
unchanged.

Author: mux

src/browser/features/Settings/Sections/ProvidersSection.tsx

@@ -78,14 +78,15 @@ import type {
   AddCustomOpenAICompatibleProviderInput,
   ProviderConfigInfo,
 } from "@/common/orpc/types";
+import type { ServiceTier } from "@/common/config/schemas/providersConfig";
 
 type MuxGatewayLoginStatus = "idle" | "starting" | "waiting" | "success" | "error";
 type CodexOauthFlowStatus = "idle" | "starting" | "waiting" | "error";
 type CopilotLoginStatus = "idle" | "starting" | "waiting" | "success" | "error";
 
 const OPENAI_SERVICE_TIER_UNSET = "unset";
 
-type OpenAIServiceTier = "auto" | "default" | "flex" | "priority";
+type OpenAIServiceTier = ServiceTier;
 type OpenAIServiceTierSelectValue = typeof OPENAI_SERVICE_TIER_UNSET | OpenAIServiceTier;
 
 function isOpenAIServiceTier(value: string): value is OpenAIServiceTier {

src/cli/run.ts

@@ -35,6 +35,7 @@ import {
   type SendMessageOptions,
   type WorkspaceChatMessage,
 } from "../common/orpc/types";
+import type { ServiceTier } from "../common/config/schemas/providersConfig";
 import { createDisplayUsage } from "../common/utils/tokens/displayUsage";
 import {
   getTotalCost,
@@ -298,7 +299,7 @@ interface CLIOptions {
   mcpConfig: boolean;
   experiment: string[];
   budget?: number;
-  serviceTier?: "auto" | "default" | "flex" | "priority";
+  serviceTier?: ServiceTier;
   use1m?: boolean;
   keepBackgroundProcesses?: boolean;
 }

src/common/config/schemas/providersConfig.ts

@@ -5,6 +5,7 @@ import { ProviderModelEntrySchema } from "./providerModelEntry";
 
 export const CacheTtlSchema = z.enum(["5m", "1h"]);
 export const ServiceTierSchema = z.enum(["auto", "default", "flex", "priority"]);
+export type ServiceTier = z.infer<typeof ServiceTierSchema>;
 export const CodexOauthDefaultAuthSchema = z.enum(["oauth", "apiKey"]);
 
 export const BaseProviderConfigSchema = z

src/node/services/providerModelFactory.ts

@@ -20,6 +20,7 @@ import {
 import { parseCodexOauthAuth } from "@/node/utils/codexOauthAuth";
 import type { Config, ProviderConfig, ProvidersConfig } from "@/node/config";
 import type { MuxProviderOptions } from "@/common/types/providerOptions";
+import type { ServiceTier } from "@/common/config/schemas/providersConfig";
 import type { ExternalSecretResolver } from "@/common/types/secrets";
 import { isOpReference } from "@/common/utils/opRef";
 import { isProviderDisabledInConfig } from "@/common/utils/providers/isProviderDisabled";
@@ -1279,7 +1280,7 @@ export class ProviderModelFactory {
           if (configServiceTier && muxProviderOptions.openai?.serviceTier == null) {
             muxProviderOptions.openai = {
               ...muxProviderOptions.openai,
-              serviceTier: configServiceTier as "auto" | "default" | "flex" | "priority",
+              serviceTier: configServiceTier as ServiceTier,
             };
           }
           if (configWireFormat === "responses" || configWireFormat === "chatCompletions") {