feat(menubar): implement MenuBarStatusView and QuickGlancePopoverView (Issue #22)

Sources/App/MacMonitorApp.swift

@@ -11,5 +11,15 @@ struct MacMonitorApp: App {
         .windowStyle(.titleBar)
         .windowToolbarStyle(.unified)
         .defaultSize(width: 960, height: 640)
+        
+        MenuBarExtra {
+            QuickGlancePopoverView(store: store)
+        } label: {
+            MenuBarStatusView(
+                cpuLoad: store.cpuLoad.totalLoad,
+                memoryPercent: store.memory.utilizationPercentage
+            )
+        }
+        .menuBarExtraStyle(.window)
     }
 }

Sources/UI/MenuBar/MenuBarStatusView.swift

@@ -0,0 +1,28 @@
+import SwiftUI
+
+public struct MenuBarStatusView: View {
+    public let cpuLoad: Double
+    public let memoryPercent: Double
+    
+    public init(cpuLoad: Double, memoryPercent: Double) {
+        self.cpuLoad = cpuLoad
+        self.memoryPercent = memoryPercent
+    }
+    
+    public var body: some View {
+        HStack(spacing: 5) {
+            Image(systemName: "cpu")
+                .font(.system(size: 11))
+            Text(String(format: "%.0f%%", cpuLoad))
+                .font(.system(size: 11, weight: .medium, design: .monospaced))
+            
+            Text("•")
+                .foregroundColor(.secondary)
+            
+            Image(systemName: "memorychip")
+                .font(.system(size: 11))
+            Text(String(format: "%.0f%%", memoryPercent))
+                .font(.system(size: 11, weight: .medium, design: .monospaced))
+        }
+    }
+}

Sources/UI/MenuBar/QuickGlancePopoverView.swift

@@ -0,0 +1,134 @@
+import SwiftUI
+
+public struct QuickGlancePopoverView: View {
+    var store: SystemTelemetryStore
+    
+    public init(store: SystemTelemetryStore) {
+        self.store = store
+    }
+    
+    public var body: some View {
+        VStack(alignment: .leading, spacing: 14) {
+            // Header
+            HStack {
+                Label("MacMonitor", systemImage: "macmini")
+                    .font(.headline)
+                Spacer()
+                Button {
+                    NSApp.activate(ignoringOtherApps: true)
+                    if let window = NSApp.windows.first(where: { $0.canBecomeMain }) {
+                        window.makeKeyAndOrderFront(nil)
+                    }
+                } label: {
+                    Image(systemName: "arrow.up.right.square")
+                        .foregroundColor(.secondary)
+                }
+                .buttonStyle(.plain)
+                .help("Open Main Window")
+            }
+            
+            Divider()
+            
+            // Core Metrics Grid
+            VStack(spacing: 8) {
+                glanceRow(
+                    icon: "cpu",
+                    title: "CPU Activity",
+                    value: String(format: "%.1f%%", store.cpuLoad.totalLoad),
+                    subtitle: "\(store.logicalCpuCount) Cores"
+                )
+                
+                glanceRow(
+                    icon: "memorychip",
+                    title: "Memory",
+                    value: String(format: "%.1f%%", store.memory.utilizationPercentage),
+                    subtitle: "\(formatBytes(store.memory.usedBytes)) / \(formatBytes(store.memory.totalBytes))"
+                )
+                
+                glanceRow(
+                    icon: "thermometer.medium",
+                    title: "Thermals",
+                    value: String(format: "%.1f°C", store.cpuThermal.packageTemperature),
+                    subtitle: "Fans: \(store.fans.map { "\(Int($0.currentRPM)) RPM" }.joined(separator: ", "))"
+                )
+                
+                glanceRow(
+                    icon: "bolt.fill",
+                    title: "Power",
+                    value: String(format: "%.1f W", store.power.systemTotalWatts),
+                    subtitle: store.batteryHealth.isCharging ? "Charging (\(Int(store.batteryHealth.healthPercent))%)" : "Battery (\(Int(store.batteryHealth.healthPercent))%)"
+                )
+                
+                glanceRow(
+                    icon: "network",
+                    title: "Network",
+                    value: "↓ \(formatBps(totalDownloadBps)) / ↑ \(formatBps(totalUploadBps))",
+                    subtitle: "\(store.networkBandwidth.count) active interfaces"
+                )
+            }
+            
+            Divider()
+            
+            // Footer action
+            HStack {
+                Text("Last updated: \(store.lastUpdateTimestamp.formatted(date: .omitted, time: .standard))")
+                    .font(.caption2)
+                    .foregroundColor(.secondary)
+                Spacer()
+                Button("Quit") {
+                    NSApplication.shared.terminate(nil)
+                }
+                .font(.caption)
+            }
+        }
+        .padding(14)
+        .frame(width: 320)
+    }
+    
+    private var totalDownloadBps: Double {
+        store.networkBandwidth.reduce(0.0) { $0 + $1.downloadBps }
+    }
+    
+    private var totalUploadBps: Double {
+        store.networkBandwidth.reduce(0.0) { $0 + $1.uploadBps }
+    }
+    
+    private func glanceRow(icon: String, title: String, value: String, subtitle: String) -> some View {
+        HStack {
+            Image(systemName: icon)
+                .frame(width: 18)
+                .foregroundColor(.accentColor)
+            VStack(alignment: .leading, spacing: 2) {
+                Text(title)
+                    .font(.caption)
+                    .foregroundColor(.secondary)
+                Text(subtitle)
+                    .font(.caption2)
+                    .foregroundColor(.secondary)
+                    .lineLimit(1)
+            }
+            Spacer()
+            Text(value)
+                .font(.subheadline)
+                .fontWeight(.semibold)
+                .fontDesign(.monospaced)
+        }
+    }
+    
+    private func formatBytes(_ bytes: UInt64) -> String {
+        let formatter = ByteCountFormatter()
+        formatter.allowedUnits = [.useAll]
+        formatter.countStyle = .memory
+        return formatter.string(fromByteCount: Int64(bytes))
+    }
+    
+    private func formatBps(_ bps: Double) -> String {
+        if bps < 1024 {
+            return String(format: "%.0f B/s", bps)
+        } else if bps < 1024 * 1024 {
+            return String(format: "%.1f KB/s", bps / 1024)
+        } else {
+            return String(format: "%.2f MB/s", bps / (1024 * 1024))
+        }
+    }
+}

Tests/MMMenuBarTests.swift

@@ -0,0 +1,18 @@
+import XCTest
+import SwiftUI
+@testable import MacMonitor
+
+final class MMMenuBarTests: XCTestCase {
+    
+    func testMenuBarStatusViewInitialization() {
+        let view = MenuBarStatusView(cpuLoad: 24.5, memoryPercent: 55.0)
+        XCTAssertEqual(view.cpuLoad, 24.5)
+        XCTAssertEqual(view.memoryPercent, 55.0)
+    }
+    
+    func testQuickGlancePopoverViewInitialization() {
+        let store = SystemTelemetryStore.shared
+        let view = QuickGlancePopoverView(store: store)
+        XCTAssertNotNil(view)
+    }
+}