chore: type Provider.list() as Record<ProviderID, Info>, delete dead code (#18123)

packages/opencode/src/provider/provider.ts

@@ -839,7 +839,7 @@ export namespace Provider {
       return true
     }
 
-    const providers: { [providerID: string]: Info } = {}
+    const providers: Record<ProviderID, Info> = {} as Record<ProviderID, Info>
     const languages = new Map<string, LanguageModelV2>()
     const modelLoaders: {
       [providerID: string]: CustomModelLoader

packages/opencode/src/provider/schema.ts

@@ -22,6 +22,7 @@ export const ProviderID = providerIdSchema.pipe(
     azure: schema.makeUnsafe("azure"),
     openrouter: schema.makeUnsafe("openrouter"),
     mistral: schema.makeUnsafe("mistral"),
+    gitlab: schema.makeUnsafe("gitlab"),
   })),
 )