Add AGENTS.md for cloud agent development environment setup

[LevBD]

Summary

Adds AGENTS.md with cloud-agent-specific development instructions for this Angular 12 todo application.

What's included

• Node.js version requirements (Node 16 for Angular 12 compatibility)
• Key commands table (install, serve, build, test)
• Known issues documentation (pre-existing test failure, Firebase auth limitations)
• Architecture notes for quick orientation

Environment Setup Verification

The development environment was fully verified:

• Build: npx ng build --configuration=development completes successfully
• Dev Server: npx ng serve runs on port 4200 with HTTP 200 response
• Tests: Karma + ChromeHeadless infrastructure works (pre-existing spec bug in repo)
• UI: App loads, renders Angular Material UI, dialogs are interactive

Demo

modo_app_demo.mp4

MoDo app homepage
Create task dialog
Task form with input

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