feat: add /design-review-ios with XcodeBuildMCP integration

[Skyfox-io]

Summary

• Adds XcodeBuildMCP integration to gstack, enabling iOS design QA directly from Claude Code
• New /design-review-ios skill builds, screenshots, and interacts with iOS apps on the simulator — MCP server preferred, CLI fallback
• Iteratively finds and fixes visual issues with atomic commits and before/after screenshot evidence

What this enables

gstack can now audit iOS apps the same way /design-review audits web apps, using the iOS Simulator via XcodeBuildMCP. The skill covers 10 design categories (~107 checklist items):

• Typography, spacing, and visual hierarchy
• Apple Human Interface Guidelines (HIG) compliance
• Accessibility (touch targets, labels, VoiceOver readiness)
• Light/dark mode parity
• AI slop detection (generic gradients, placeholder copy, stock patterns)
• Multi-device matrix testing (iPhone SE → iPad)

Integration architecture

The skill auto-detects the best integration mode at startup:

1. MCP server (preferred): If XcodeBuildMCP is configured as an MCP server, the skill calls its tools directly (build_run_sim, screenshot, tap, snapshot_ui, etc.) — no Bash, no PATH issues, no DEVELOPER_DIR workaround
2. CLI fallback: If no MCP tools are available, falls back to the xcodebuildmcp CLI via Bash

This means zero-config for users who already have XcodeBuildMCP set up as an MCP server (claude mcp add xcodebuildmcp).

How it works

1. Detects the Xcode project, scheme, and simulator via discover_projs / list_schemes / list_sims
2. Builds and launches the app via build_run_sim
3. Screenshots and inspects the accessibility tree via screenshot and snapshot_ui
4. Navigates the app using UI automation tools (tap, gesture, swipe)
5. Audits every reachable screen against HIG + the project's design system
6. Fixes issues in source code, commits atomically, rebuilds, and re-screenshots to verify

Requirements

• XcodeBuildMCP — either as an MCP server (recommended: claude mcp add xcodebuildmcp -- npx -y xcodebuildmcp@latest mcp) or CLI (brew install getsentry/xcodebuildmcp/xcodebuildmcp)
• Xcode + iOS Simulator
• macOS only (iOS Simulator requirement)

Test plan

• Tested on a live iOS project(s). Full audit cycle with screenshot capture, issue detection, and fix verification in both MCP and CLI modes
• Reviewer can invoke /design-review-ios on any iOS project with XcodeBuildMCP configured (MCP server or CLI)

[Skyfox-io]

Updated: MCP-first architecture

Reworked this from CLI-only to MCP-first with CLI fallback. XcodeBuildMCP is fundamentally an MCP server, and the CLI is the secondary interface. Making MCP the primary integration means:

• Zero-config for users who already have XcodeBuildMCP as an MCP server
• No DEVELOPER_DIR workaround needed
• No PATH/binary detection issues
• Structured tool calls instead of parsing bash stdout

CLI remains fully supported as a fallback for users without the MCP server configured.

Force-pushed to squash into a clean commit since the architectural premise changed.