feat: Add favicon provider setting (Google vs DuckDuckGo)

[dernerl]

⚙️ Favicon Provider Settings

Closes #3

✨ What's New

Adds a Favicon Provider setting that allows users to choose between Google and DuckDuckGo favicon services.

🎯 Motivation

Privacy Considerations:

• Google Favicon Service: More reliable, comprehensive coverage, but tracks requests
• DuckDuckGo Favicon Service: Privacy-focused, no tracking

📦 Implementation

1. FaviconProvider Enum

enum FaviconProvider: String, CaseIterable, Identifiable, Codable {
    case google = "Google"
    case duckduckgo = "DuckDuckGo"
    
    func faviconURL(for domain: String) -> URL? {
        switch self {
        case .google:
            return URL(string: "https://www.google.com/s2/favicons?domain=\(domain)&sz=32")
        case .duckduckgo:
            return URL(string: "https://icons.duckduckgo.com/ip3/\(domain).ico")
        }
    }
}

2. Settings Integration

• New "Appearance" section in Settings (⌘,)
• Picker to select provider (Google or DuckDuckGo)
• Info text explaining the difference
• Persisted via @AppStorage

3. Dynamic Favicon Loading

• FavoriteRowView reads provider from AppStorage
• Favicon URLs generated based on selected provider
• Changes take effect immediately (no restart required)

🖼️ Settings UI

New Appearance Section:

Settings
  └─ Appearance
       ├─ Favicon Provider: [Google ▼]
       │    - Google
       │    - DuckDuckGo (Privacy)
       └─ ℹ️ More reliable, comprehensive coverage

🔧 API Endpoints

Google:

• URL: https://www.google.com/s2/favicons?domain={domain}&sz=32
• ✅ Reliable, comprehensive coverage
• ✅ Supports size parameter (32px)
• ⚠️ Tracks requests

DuckDuckGo:

• URL: https://icons.duckduckgo.com/ip3/{domain}.ico
• ✅ Privacy-focused, no tracking
• ✅ Fast, reliable
• ⚠️ Fixed size (ICO format)

✅ Testing

Tested Scenarios:

• ✅ Default provider is Google
• ✅ Switching provider in Settings updates favicons immediately
• ✅ AppStorage persists selection across app restarts
• ✅ Both providers load favicons correctly
• ✅ Fallback to globe icon works for both providers
• ✅ www. prefix is correctly stripped from domains

📝 Changes

New Files:

• FaviconProvider.swift - Provider enum with URL generation logic

Modified Files:

• SettingsView.swift - Added Appearance section with provider picker
• ContentView.swift - Use selected provider for favicon URLs

🎨 UI Improvements

• Settings window height increased to 380px (was 300px)
• Info icon with description for selected provider
• Picker uses display names ("DuckDuckGo (Privacy)")

🔐 Privacy Benefits

Users can now choose DuckDuckGo if they prefer:

• ✅ No tracking of favicon requests
• ✅ Privacy-respecting alternative
• ✅ Still reliable for most domains

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Ready for review! 🚀