feat: implement Speedy Circles game

[devin-ai-integration]

Summary

Implements the Speedy Circles game — a tap-to-score iOS game built entirely in SwiftUI.

Gameplay:

• Start screen lets the user pick a time interval (2.0s, 3.0s, or 5.0s) then tap Start
• A colored circle appears at a random position; a countdown begins
• Tapping the circle before time expires: score increments, circle shrinks (min 44pt), changes color, moves to a new random position, timer resets
• Missing a tap ends the game — final score is shown with a Retry button back to the start screen

Implementation details:

• GameModel (@Observable) manages all game state: phase, score, deadline, circle position/size/color
• Timer driven by Combine Timer.publish at 60fps via .onReceive — no manual Timer/Task management
• Circle stays within screen bounds with edge padding + HUD top padding
• Smooth spring animations on circle movement/resize, easeInOut fade transitions between screens
• Progress bar and numeric countdown in the HUD; bar/text turn red when < 30% time remaining
• Accessibility identifiers on all interactive elements for lim CLI testing

Demo Videos

Full gameplay (5.0s interval, 5 circles tapped):

Retry flow (2.0s interval, 3 circles tapped):

Preview: Live simulator preview

Review & Testing Checklist for Human

• Launch the app and verify the start screen shows all three interval buttons (2.0s, 3.0s, 5.0s) with 3.0s selected by default
• Play a round: confirm score increments, circle moves/shrinks/recolors, timer resets on each tap
• Let the timer expire and verify the Game Over screen shows the correct score and Retry returns to start
• Test with 2.0s interval to confirm the game is noticeably faster
• Verify the circle never appears outside visible screen bounds or under the HUD

Recommended test plan: Open the preview link above, select each interval, play a few rounds, and verify animations are smooth and scoring is correct.

Notes

• The circle minimum size is 44pt (Apple HIG minimum tap target)
• Circle shrinks by 4pt per successful tap, so it takes ~14 taps from 100pt to reach minimum
• Uses PBXFileSystemSynchronizedRootGroup so the new GameModel.swift is auto-included by Xcode
• Circle is a proper accessibility element (.accessibilityElement(), .accessibilityAddTraits(.isButton)) for automated testing

Link to Devin session: https://app.devin.ai/sessions/3af8ea536a77488b9f6c45e82dcfe16b
Requested by: @muvaf

[devin-ai-integration]

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Limrun Preview

Platform	Commit	Preview
iOS	6a852b9	Open Simulator Preview →
iOS	6a852b9	Install to Device →

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