feat(design-system): adaptive grid layout, content width env, and UI polish

Fix AtlasSpacing.screenH value (24 -> 28). Add adaptiveMetricColumns
for responsive grid layouts and atlasContentWidth environment key.
Enhance AtlasEmptyState with optional action button. Brand-tint
ProgressView controls. Add AtlasPresentationHelpers.

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

Packages/AtlasDesignSystem/Sources/AtlasDesignSystem/AtlasBrand.swift

@@ -135,7 +135,7 @@ public enum AtlasSpacing {
     /// 24pt — screen-level vertical rhythm.
     public static let xxl: CGFloat = 24
     /// 28pt — screen horizontal margin.
-    public static let screenH: CGFloat = 24
+    public static let screenH: CGFloat = 28
     /// 32pt — large section separation.
     public static let section: CGFloat = 32
 }
@@ -244,6 +244,45 @@ public enum AtlasLayout {
     public static let sidebarIdealWidth: CGFloat = 220
     /// Sidebar icon container size (pill-style like System Settings).
     public static let sidebarIconSize: CGFloat = 32
+
+    /// Returns an adaptive column layout based on available width.
+    /// - 3 columns for widths >= 640
+    /// - 2 columns for widths >= 420
+    /// - 1 column for narrower widths
+    public static func adaptiveMetricColumns(for width: CGFloat) -> [GridItem] {
+        let spacing = AtlasSpacing.lg
+        switch width {
+        case 640...:
+            return [
+                GridItem(.flexible(minimum: 180), spacing: spacing),
+                GridItem(.flexible(minimum: 180), spacing: spacing),
+                GridItem(.flexible(minimum: 180), spacing: spacing),
+            ]
+        case 420...:
+            return [
+                GridItem(.flexible(minimum: 180), spacing: spacing),
+                GridItem(.flexible(minimum: 180), spacing: spacing),
+            ]
+        default:
+            return [
+                GridItem(.flexible(minimum: 180), spacing: spacing),
+            ]
+        }
+    }
+}
+
+// MARK: - Content Width Environment Key
+
+private struct AtlasContentWidthKey: EnvironmentKey {
+    static let defaultValue: CGFloat = 920
+}
+
+public extension EnvironmentValues {
+    /// The actual content width injected by `AtlasScreen`.
+    var atlasContentWidth: CGFloat {
+        get { self[AtlasContentWidthKey.self] }
+        set { self[AtlasContentWidthKey.self] = newValue }
+    }
 }
 
 // MARK: - Icon Tokens

Packages/AtlasDesignSystem/Sources/AtlasDesignSystem/AtlasDesignSystem.swift

@@ -90,18 +90,20 @@ public struct AtlasScreen<Content: View>: View {
                 Group {
                     if useScrollView {
                         ScrollView {
-                            contentStack(horizontalPadding: horizontalPadding)
+                            contentStack(horizontalPadding: horizontalPadding, containerWidth: proxy.size.width)
                         }
                     } else {
-                        contentStack(horizontalPadding: horizontalPadding)
+                        contentStack(horizontalPadding: horizontalPadding, containerWidth: proxy.size.width)
                     }
                 }
             }
         }
     }
 
-    private func contentStack(horizontalPadding: CGFloat) -> some View {
-        VStack(alignment: .leading, spacing: AtlasSpacing.xxl) {
+    private func contentStack(horizontalPadding: CGFloat, containerWidth: CGFloat) -> some View {
+        let contentWidth = min(AtlasLayout.maxReadingWidth, containerWidth - horizontalPadding * 2)
+
+        return VStack(alignment: .leading, spacing: AtlasSpacing.xxl) {
             header
             content
         }
@@ -109,6 +111,7 @@ public struct AtlasScreen<Content: View>: View {
         .padding(.horizontal, horizontalPadding)
         .padding(.vertical, AtlasSpacing.xxl)
         .frame(maxWidth: .infinity, maxHeight: .infinity, alignment: .topLeading)
+        .environment(\.atlasContentWidth, max(0, contentWidth))
     }
 
     private func resolvedHorizontalPadding(for width: CGFloat) -> CGFloat {
@@ -468,12 +471,16 @@ public struct AtlasEmptyState: View {
     private let detail: String
     private let systemImage: String
     private let tone: AtlasTone
+    private let actionTitle: String?
+    private let onAction: (() -> Void)?
 
-    public init(title: String, detail: String, systemImage: String, tone: AtlasTone = .neutral) {
+    public init(title: String, detail: String, systemImage: String, tone: AtlasTone = .neutral, actionTitle: String? = nil, onAction: (() -> Void)? = nil) {
         self.title = title
         self.detail = detail
         self.systemImage = systemImage
         self.tone = tone
+        self.actionTitle = actionTitle
+        self.onAction = onAction
     }
 
     public var body: some View {
@@ -509,6 +516,13 @@ public struct AtlasEmptyState: View {
                     .multilineTextAlignment(.center)
                     .fixedSize(horizontal: false, vertical: true)
             }
+
+            if let actionTitle, let onAction {
+                Button(actionTitle) {
+                    onAction()
+                }
+                .buttonStyle(.atlasSecondary)
+            }
         }
         .frame(maxWidth: .infinity)
         .padding(AtlasSpacing.section)
@@ -520,7 +534,7 @@ public struct AtlasEmptyState: View {
             RoundedRectangle(cornerRadius: AtlasRadius.xl, style: .continuous)
                 .strokeBorder(Color.primary.opacity(0.06), lineWidth: 1)
         )
-        .accessibilityElement(children: .ignore)
+        .accessibilityElement(children: onAction != nil ? .contain : .ignore)
         .accessibilityLabel(Text(title))
         .accessibilityValue(Text(detail))
     }
@@ -543,6 +557,7 @@ public struct AtlasLoadingState: View {
             HStack(spacing: AtlasSpacing.md) {
                 ProgressView()
                     .controlSize(.small)
+                    .tint(AtlasColor.brand)
                     .accessibilityHidden(true)
 
                 Text(title)
@@ -557,6 +572,7 @@ public struct AtlasLoadingState: View {
             if let progress {
                 ProgressView(value: progress, total: 1)
                     .controlSize(.large)
+                    .tint(AtlasColor.brand)
             }
         }
         .frame(maxWidth: .infinity, alignment: .leading)

Packages/AtlasDesignSystem/Sources/AtlasDesignSystem/AtlasPresentationHelpers.swift

@@ -0,0 +1,85 @@
+import AtlasDomain
+import SwiftUI
+
+// MARK: - Shared Domain → UI Mappings
+//
+// These public extensions centralise the mapping from domain enums
+// to AtlasTone and SF Symbol strings so every feature module shares
+// the same visual language without duplicating private extensions.
+
+public extension TaskStatus {
+    var atlasTone: AtlasTone {
+        switch self {
+        case .queued:
+            return .neutral
+        case .running:
+            return .warning
+        case .completed:
+            return .success
+        case .failed, .cancelled:
+            return .danger
+        }
+    }
+}
+
+public extension RiskLevel {
+    var atlasTone: AtlasTone {
+        switch self {
+        case .safe:
+            return .success
+        case .review:
+            return .warning
+        case .advanced:
+            return .danger
+        }
+    }
+}
+
+public extension TaskKind {
+    var atlasSystemImage: String {
+        switch self {
+        case .scan:
+            return "sparkles"
+        case .executePlan:
+            return "play.circle"
+        case .uninstallApp:
+            return "trash"
+        case .restore:
+            return "arrow.uturn.backward.circle"
+        case .inspectPermissions:
+            return "lock.shield"
+        }
+    }
+}
+
+public extension ActionItem.Kind {
+    var atlasSystemImage: String {
+        switch self {
+        case .removeCache:
+            return "trash"
+        case .removeApp:
+            return "app.badge.minus"
+        case .archiveFile:
+            return "archivebox"
+        case .inspectPermission:
+            return "lock.shield"
+        }
+    }
+}
+
+public enum AtlasCategoryIcon {
+    public static func systemImage(for category: String) -> String {
+        switch category.lowercased() {
+        case "developer":
+            return "hammer"
+        case "system":
+            return "gearshape.2"
+        case "apps":
+            return "square.stack.3d.up"
+        case "browsers":
+            return "globe"
+        default:
+            return "sparkles"
+        }
+    }
+}