Add AGENTS.md with Cursor Cloud dev environment instructions

[rishabhsingh971]

Summary

Adds AGENTS.md with Cursor Cloud-specific instructions for setting up the Android development environment.

What was set up

• JDK 11 — required because AGP 3.3.0 is incompatible with JDK 17+
• Android SDK — platform 28, build-tools 28.0.3, command-line tools installed at /opt/android-sdk
• local.properties — points to the SDK location (not committed)
• Environment variables (JAVA_HOME, ANDROID_SDK_ROOT) configured in ~/.bashrc

Verified commands

Command	Result
./gradlew assembleDebug	BUILD SUCCESSFUL — 50MB debug APK produced
./gradlew test	BUILD SUCCESSFUL — all unit tests pass
./gradlew lint	Lint runs correctly; exits non-zero due to 16 pre-existing errors in the codebase

Build and test evidence

build_and_test_output.log

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