Document iOS platform requirement for Cloud Agent env setup

[aj327]

Summary

Set up (as far as possible) and documented the development environment for CheckList. CheckList is a native iOS app (Swift 3.0, UIKit, Core Data, storyboards) that requires macOS + Xcode to build and run. It cannot be built, run, linted, or tested on the Linux Cloud Agent VM.

This adds AGENTS.md with durable, non-obvious setup guidance for future Cloud Agents so they don't waste effort attempting a Linux build.

Findings (evidence)

• No Swift/Xcode toolchain on the VM: swift, swiftc, xcodebuild, xcrun all NOT FOUND.
• Swift toolchain hosts are blocked by egress (download.swift.org → connection reset).
• Sources import Apple-only frameworks unavailable on Linux: import UIKit, import CoreData.
• Xcode project targets the iOS SDK: SDKROOT = iphoneos, IPHONEOS_DEPLOYMENT_TARGET = 10.3, product-type = com.apple.product-type.application, SWIFT_VERSION = 3.0.
• No dependency manifests (no CocoaPods/Carthage/SPM) and no test target.

This is a platform incompatibility, not a missing dependency — no Linux install step can enable building an iOS app here.

Changes

• Add AGENTS.md with a ## Cursor Cloud specific instructions section documenting the platform requirement, project overview, what is/isn't possible on Linux, and the macOS/Xcode build & run steps.

Update script

Registered a minimal no-op startup refresh (there are no Linux-installable dependencies for this iOS project).