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/src/modes/interactive/components/login-dialog.ts

@@ -1,4 +1,4 @@
-import { getOAuthProviders } from "@mariozechner/pi-ai";
+import { getOAuthProviders } from "@mariozechner/pi-ai/oauth";
 import { Container, type Focusable, getEditorKeybindings, Input, Spacer, Text, type TUI } from "@mariozechner/pi-tui";
 import { exec } from "child_process";
 import { theme } from "../theme/theme.js";

packages/coding-agent/src/modes/interactive/components/oauth-selector.ts

@@ -1,4 +1,5 @@
-import { getOAuthProviders, type OAuthProviderInterface } from "@mariozechner/pi-ai";
+import type { OAuthProviderInterface } from "@mariozechner/pi-ai";
+import { getOAuthProviders } from "@mariozechner/pi-ai/oauth";
 import { Container, getEditorKeybindings, Spacer, TruncatedText } from "@mariozechner/pi-tui";
 import type { AuthStorage } from "../../../core/auth-storage.js";
 import { theme } from "../theme/theme.js";