Add external Codemode runtime adapter example

[scuffi]

Summary

• adapt @cloudflare/codemode to the Computer runtime through a private trusted module
• scope providers and connectors to one serialized execution token at a time
• preserve finite structured values, typed binary data, and undefined across the runtime bridge
• isolate generated codec helpers from provider namespace shadowing
• provide one focused Durable Object and POST /run reference harness
• keep Codemode outside @cloudflare/computer core

Trust model

The adapter backend is host-owned and private. Execution tokens grant only the providers/connectors installed for that call. The executor serializes calls, the dispatcher rejects overlapping tokens, and authority is revoked before retained execution cleanup. The checked-in HTTP route accepts no caller code, provider set, backend, or Workspace identity. It remains an unauthenticated local harness; production services must add tenant identity, authorization, and quotas.

Validation

• npm run check
• npm run build --workspaces --if-present
• npm run typecheck
• npm test --workspaces --if-present
• Codemode: 2 files / 13 tests
• npx wrangler deploy --dry-run --outdir /tmp/computer-codemode-final
• npm ci --ignore-scripts --dry-run --no-audit --no-fund
• git diff --check origin/main..HEAD

[pkg-pr-new]

Open in StackBlitz

npm i https://pkg.pr.new/cloudflare/computer/@cloudflare/computer@28

commit: 509bf0d

[aron-cf]

Trying to figure out if we need this on top of the existing backend. I'm not sure what it would be used for. What are your thoughts?