SDK sandbox provisioning: built-in providers, docs restructure, and quickstart overhaul

- Add built-in sandbox providers (local, docker, e2b, daytona, vercel, cloudflare) to the TypeScript SDK so users import directly instead of passing client instances
- Restructure docs: rename architecture to orchestration-architecture, add new architecture page for server overview, improve getting started flow
- Rewrite quickstart to be TypeScript-first with provider CodeGroup and custom provider accordion
- Update all examples to use new provider APIs
- Update persist drivers and foundry for new SDK surface

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

examples/docker/package.json

@@ -9,10 +9,10 @@
   "dependencies": {
     "@sandbox-agent/example-shared": "workspace:*",
     "dockerode": "latest",
+    "get-port": "latest",
     "sandbox-agent": "workspace:*"
   },
   "devDependencies": {
-    "@types/dockerode": "latest",
     "@types/node": "latest",
     "tsx": "latest",
     "typescript": "latest",