Add AGENTS.md with Cursor Cloud specific instructions

[alokedesai]

Description

Adds AGENTS.md with Cloud Agent-specific development environment instructions, documenting non-obvious gotchas discovered during setup:

• Build/run/lint/test command reference for the OSS binary
• corepack/yarn 4 requirement for command-signatures-v2 crate
• libstdc++.so symlink issue on Ubuntu 24.04
• protoc version requirements
• How to skip interactive common-skills prompts in automated environments
• Integration test display server requirements

Linked Issue

N/A — this is development infrastructure for Cursor Cloud Agents.

• Where appropriate, screenshots or a short video of the implementation are included below.

Testing

Environment was fully set up and validated:

• I have manually tested my changes locally with ./script/run

Screenshots / Videos

Warp terminal launching and executing echo "Hello from Warp":

CHANGELOG-NONE

  

[cla-bot]

Thank you for your pull request and welcome to our community. We require contributors to sign our Contributor License Agreement, and we don't seem to have the users @cursoragent on file. In order for us to review and merge your code, each contributor must visit https://cla.warp.dev to read and agree to our CLA. Once you have done so, please comment @cla-bot check to trigger another check.