chore(vendor): import pi 0.85.1

Imported as a linear vendor commit so forge rebases do not replay the upstream root tree.

git-subtree-dir: third_party/pi

git-subtree-split: d981de1229ef899957bbe968bc8dcda02a21f477

third_party/pi/packages/ai/src/providers/github-copilot.ts

@@ -0,0 +1,34 @@
+import { anthropicMessagesApi } from "../api/anthropic-messages.lazy.ts";
+import { openAICompletionsApi } from "../api/openai-completions.lazy.ts";
+import { openAIResponsesApi } from "../api/openai-responses.lazy.ts";
+import { envApiKeyAuth, lazyOAuth } from "../auth/helpers.ts";
+import { loadGitHubCopilotOAuth } from "../auth/oauth/load.ts";
+import { createProvider, type Provider } from "../models.ts";
+import { GITHUB_COPILOT_MODELS } from "./github-copilot.models.ts";
+
+export function githubCopilotProvider(): Provider<"anthropic-messages" | "openai-completions" | "openai-responses"> {
+	return createProvider({
+		id: "github-copilot",
+		name: "GitHub Copilot",
+		baseUrl: "https://api.individual.githubcopilot.com",
+		auth: {
+			apiKey: envApiKeyAuth("GitHub Copilot token", ["COPILOT_GITHUB_TOKEN"]),
+			oauth: lazyOAuth({ name: "GitHub Copilot", isSubscription: true, load: loadGitHubCopilotOAuth }),
+		},
+		models: Object.values(GITHUB_COPILOT_MODELS),
+		filterModels: (models, credential) => {
+			if (credential?.type !== "oauth") return models;
+			const availableModelIds = credential.availableModelIds;
+			if (!Array.isArray(availableModelIds) || !availableModelIds.every((id) => typeof id === "string")) {
+				return models;
+			}
+			const available = new Set(availableModelIds);
+			return models.filter((model) => available.has(model.id));
+		},
+		api: {
+			"anthropic-messages": anthropicMessagesApi(),
+			"openai-completions": openAICompletionsApi(),
+			"openai-responses": openAIResponsesApi(),
+		},
+	});
+}