Add Apple Intelligence provider (Phase 1 — on-device)

- New AppleFoundationProvider using FoundationModels framework (macOS 27+)
- Streaming via streamResponse(to:) → ResponseStream<String> snapshot deltas
- Session built with system prompt + conversation history injected as instructions text
- Full error mapping: context exceeded, guardrail violation, rate limit, availability states
- Settings.Provider.appleOnDevice case wired through ProviderRegistry, Color+Extensions, CreditsView
- inferProvider() detects "apple-" prefix model IDs
- Settings → General: Apple Intelligence section with live availability badge and deep link to System Settings

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

oAI/Views/Screens/CreditsView.swift

@@ -80,6 +80,17 @@ struct CreditsView: View {
                             .font(.system(size: 40))
                             .foregroundColor(.green)
                             .padding(.top)
+
+                    case .appleOnDevice:
+                        Text("Apple Intelligence")
+                            .font(.headline)
+                        Text("On-device and free — no credits or API key needed.")
+                            .font(.body)
+                            .foregroundColor(.secondary)
+                        Image(systemName: "apple.logo")
+                            .font(.system(size: 40))
+                            .foregroundColor(.secondary)
+                            .padding(.top)
                     }
                 }
 

oAI/Views/Screens/SettingsView.swift

@@ -25,6 +25,7 @@
 
 import SwiftUI
 import UniformTypeIdentifiers
+import FoundationModels
 
 struct SettingsView: View {
     @Environment(\.dismiss) var dismiss
@@ -306,6 +307,29 @@ It's better to admit "I need more information" or "I cannot do that" than to fak
             }
         }
 
+        // Apple Intelligence
+        VStack(alignment: .leading, spacing: 6) {
+            sectionHeader("Apple Intelligence")
+            formSection {
+                row("Status") {
+                    appleIntelligenceStatusBadge
+                }
+                rowDivider()
+                row("Model") {
+                    Text("On-Device (4K context)")
+                        .foregroundStyle(.secondary)
+                }
+                rowDivider()
+                row("") {
+                    Button("Open Apple Intelligence Settings") {
+                        if let url = URL(string: "x-apple.systempreferences:com.apple.preference.aisettings") {
+                            NSWorkspace.shared.open(url)
+                        }
+                    }
+                }
+            }
+        }
+
         // Features
         VStack(alignment: .leading, spacing: 6) {
             sectionHeader("Features")
@@ -2649,6 +2673,28 @@ It's better to admit "I need more information" or "I cannot do that" than to fak
         formatter.unitsStyle = .full
         return formatter.localizedString(for: date, relativeTo: .now)
     }
+
+    @ViewBuilder
+    private var appleIntelligenceStatusBadge: some View {
+        let availability = SystemLanguageModel.default.availability
+        switch availability {
+        case .available:
+            Label("Available", systemImage: "checkmark.circle.fill")
+                .foregroundStyle(.green)
+        case .unavailable(.deviceNotEligible):
+            Label("Not supported on this Mac", systemImage: "xmark.circle.fill")
+                .foregroundStyle(.red)
+        case .unavailable(.appleIntelligenceNotEnabled):
+            Label("Not enabled — open Apple Intelligence Settings", systemImage: "exclamationmark.circle.fill")
+                .foregroundStyle(.orange)
+        case .unavailable(.modelNotReady):
+            Label("Model downloading…", systemImage: "arrow.down.circle.fill")
+                .foregroundStyle(.orange)
+        default:
+            Label("Unavailable", systemImage: "questionmark.circle.fill")
+                .foregroundStyle(.secondary)
+        }
+    }
 }
 
 #Preview {