chore: bump templates and examples to lang-core 0.2.18, drop thesys-server

[devin-ai-integration]

What

@openuidev/lang-core@0.2.18 ships artifactTool from @openuidev/lang-core/cloud (#1146), so @openuidev/thesys-server can be deprecated. This pins every template and example to 0.2.18 and removes the thesys-server dependency from the Cloud template.

Changes

• templates/* and examples/**: @openuidev/lang-core → 0.2.18 (was 0.2.17, 0.2.15 in openui-self-hosted)
• templates/openui-cloud: drop @openuidev/thesys-server; route.ts and overlays/langgraph/src/agent.ts now import { artifactTool } from "@openuidev/lang-core/cloud"; README updated
• Lockfiles regenerated: template package-lock.json (base + each overlay, overlay locks built from base package.json + manifest.json, vercel-eve with its .npmrc), and both pnpm-lock.yaml / package-lock.json for every example. The stale openui-self-hosted overlay locks also picked up react-ui ^0.13.10 / zustand ^4.5.5 from the current base package.json.

Test Plan

• Verified locally
  • npm ci on a copy of templates/openui-cloud + tsc --noEmit passes for the base template; require("@openuidev/lang-core/cloud").artifactTool is a function
  • No thesys-server references remain in templates/examples (source, manifests, or locks)

Checklist

• I linked a related issue, if applicable
• I updated docs/README when needed
• I considered backwards compatibility

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Open in Devin Desktop: https://app.devin.ai/desktop/session/4b10770523fa413bbd7b173e23189c1f?variant=devin

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Project	Deployment	Actions	Updated
openui-docs	Ready	Preview	Sep 10, 2026 9:56am UTC

[devin-ai-integration]

Tested the Cloud template from this branch locally (copied templates/openui-cloud, since the CLI scaffolds from main):

• npm ci from the committed lock, next build, and typecheck all pass; installed @openuidev/lang-core is 0.2.18 and no thesys-server package is present.
• Real Cloud chat streams; the presentation artifactTool (now from @openuidev/lang-core/cloud) generated a 4-slide deck that rendered in the detailed view. Both /api/chat calls returned 200, no server errors.
• Caveat: during artifact streaming the browser logs caught TypeError: Cannot read properties of undefined (reading 'labels') from the @openuidev/thesys chart renderer (partial chart data mid-stream); the final chart renders fine. @openuidev/thesys is unchanged in this PR, so this appears unrelated, but I didn't confirm against main.
• LangGraph overlay not exercised.

Rendered presentation	Console error mid-stream