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/ai/package.json

@@ -5,11 +5,23 @@
 	"type": "module",
 	"main": "./dist/index.js",
 	"types": "./dist/index.d.ts",
+	"exports": {
+		".": {
+			"types": "./dist/index.d.ts",
+			"import": "./dist/index.js"
+		},
+		"./oauth": {
+			"types": "./oauth.d.ts",
+			"import": "./oauth.js"
+		}
+	},
 	"bin": {
 		"pi-ai": "./dist/cli.js"
 	},
 	"files": [
 		"dist",
+		"oauth.js",
+		"oauth.d.ts",
 		"README.md"
 	],
 	"scripts": {