Add Testing Coverage for Different Platforms and Devices

# Add Testing Coverage for Different Platforms and Devices

**Labels:** low, testing, enhancement

## Problem
No documented testing on different iOS/macOS versions or Metal GPU families.

## Current State
- No documented testing matrix
- Unknown compatibility with different OS versions
- Unknown compatibility with different Metal GPU families
- No testing on different device types (iPhone, iPad, Mac)

## Impact
- Potential issues on specific platforms
- Unknown compatibility boundaries
- Risk of bugs on untested configurations
- Difficult to support users on different platforms

## Suggested Solution

### 1. Define Testing Matrix
```
macOS:
- macOS 14.0 (minimum supported)
- macOS 14.5 (latest)
- macOS 15.0 (beta)

iOS:
- iOS 17.0 (minimum supported)
- iOS 17.5 (latest)
- iOS 18.0 (beta)

Devices:
- iPhone 12 Pro (A14)
- iPhone 15 Pro (A17)
- iPad Pro (M2)
- MacBook Pro (M1/M2/M3)

Metal GPU Families:
- Apple 7 (A14)
- Apple 8 (A15-A16)
- Apple 9 (A17)
- Mac 2 (M1-M3)
```

### 2. Add Platform-Specific Tests
Test platform-specific behaviors and edge cases.

### 3. Document Supported Configurations
Update README with tested configurations.

### 4. Add CI/CD Matrix Testing
Test on multiple OS versions in CI pipeline.

### 5. Create Compatibility Guide
Document known issues and workarounds for specific platforms.

## Acceptance Criteria
- [ ] Testing matrix defined and documented
- [ ] Tests run on multiple platforms
- [ ] Platform-specific issues identified and documented
- [ ] CI/CD tests multiple configurations
- [ ] Compatibility guide created
- [ ] README updated with supported platforms

**Priority:** Low
**Effort:** Medium (2-3 weeks)

Start by reviewing the README and the CI pipeline, then map the proposed macOS, iOS, device, and Metal GPU configurations against the current project setup. Done means a documented testing matrix, platform-specific test results and issues, CI coverage for multiple configurations, a compatibility guide, and README updates.

Written by the indexing model from the issue text.