chore(vendor): import pi 1.3.0

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: 71023aec1546d6d677a65669c5665c0927ce0dd0

third_party/pi/packages/evals/evals/models.docs.eval.ts

@@ -0,0 +1,40 @@
+import { describeEval, StructuredOutputJudge } from "vitest-evals";
+import { inspectAddedModel, type AddedModelOutput } from "./configured-runtime.ts";
+import { createPiDocumentationEvalHarness } from "../src/harness.ts";
+
+const PROVIDER_ID = "openai";
+const MODEL_ID = "fixture-chat";
+const MODEL_NAME = "Fixture Chat";
+
+const expected: AddedModelOutput = {
+	result: {
+		model: {
+			id: MODEL_ID,
+			name: MODEL_NAME,
+			provider: PROVIDER_ID,
+			reasoning: true,
+			input: ["text"],
+			cost: { input: 0, output: 0, cacheRead: 0, cacheWrite: 0 },
+			contextWindow: 32768,
+			maxTokens: 4096,
+		},
+		existingModelsPreserved: true,
+	},
+};
+
+const harness = createPiDocumentationEvalHarness({
+	output: ({ session }) => inspectAddedModel(session.modelRuntime, PROVIDER_ID, MODEL_ID),
+});
+const judge = StructuredOutputJudge({ expected, match: "strict", allowExtras: false });
+
+describeEval("Add model to existing provider", { harness, judges: [judge], judgeThreshold: null }, (it) => {
+	it("adds the model without replacing existing models", async ({ run }) => {
+		await run([
+			{
+				type: "prompt",
+				content: `Configure this running Pi installation with a new \`${PROVIDER_ID}/${MODEL_ID}\` model. Do not create project-local configuration. Show it as “${MODEL_NAME}”. It accepts text, supports reasoning, has a 32,768-token context window and a 4,096-token maximum output, and has no usage cost.`,
+			},
+			{ type: "reload" },
+		]);
+	});
+});