docs: describe Cloud Agent local development constraints - #9166

Summary

Documents how to run Sim on a Cloud Agent VM: Node 24 must come before /exec-daemon/node, Postgres 17 and Redis are started without systemd, and the app should use bun run dev:full:capped so the Next.js heap does not exhaust a 16GB machine.

Fixes #(issue)

Product update (if relevant)

Future Cloud Agents get the local-dev constraints in CLAUDE.md (AGENTS.md is a symlink to that file). No product behavior change.

Type of Change

• Bug fix
• New feature
• Breaking change
• Documentation
• Other: ___________

Testing

Verified on a Cloud Agent VM: install script ran twice, the start script brought Next.js (/signup 200) and realtime (/health 200) up, browser signup created a workspace, and POST /api/workflows created a workflow named Hello. bun run --cwd apps/realtime type-check passed, and bun run --cwd packages/logger test passed (23 tests). Draft environment build bld-20261017-280df879-fed1-4066-b520-114fe084e013 succeeded.

Checklist

• Code follows project style guidelines
• Self-reviewed my changes
• Tests added/updated and passing
• No new warnings introduced
• I confirm that I have read and agree to the terms outlined in the Contributor License Agreement (CLA)

Screenshots/Videos