fix(ai,coding-agent): make pi-ai browser-safe and move OAuth runtime exports

- add browser smoke bundling check to root check + pre-commit

- lazy-load Bedrock provider registration to avoid browser graph traversal

- remove top-level OAuth runtime exports from @mariozechner/pi-ai

- add @mariozechner/pi-ai/oauth subpath export and update coding-agent imports

- move proxy dispatcher init to coding-agent CLI (Node-only)

- document Bedrock/OAuth browser limitations

closes #1814

packages/coding-agent/test/model-registry.test.ts

@@ -2,7 +2,8 @@ import { existsSync, mkdirSync, readFileSync, rmSync, writeFileSync } from "node
 import { tmpdir } from "node:os";
 import { join } from "node:path";
 import type { Api, Context, Model, OpenAICompletionsCompat } from "@mariozechner/pi-ai";
-import { getApiProvider, getOAuthProvider } from "@mariozechner/pi-ai";
+import { getApiProvider } from "@mariozechner/pi-ai";
+import { getOAuthProvider } from "@mariozechner/pi-ai/oauth";
 import { afterEach, beforeEach, describe, expect, test } from "vitest";
 import { AuthStorage } from "../src/core/auth-storage.js";
 import { clearApiKeyCache, ModelRegistry } from "../src/core/model-registry.js";