iOS: left side drawer (calendars + groups + nav) and opt-in top-bar colour

Replace the top-bar menu popup with an off-canvas left drawer, opened by the
hamburger or a narrow left-edge swipe (kept off the content area so month/week
swipe stay free). The drawer hosts the calendar visibility list, a view
switcher, group switching, and quick access to Settings/Accounts/Profile/
Groups/Server plus sync and logout.

- extract the filter list into reusable CalendarFilterContent (shared by the
  drawer and the still-present CalendarFilterSheet); the sheet is now a thin
  wrapper
- new CalendarDrawer view; CalendarHostView hosts it as a ZStack overlay with a
  scrim and edge-swipe gesture, and presents drawer destinations as sheets
- opt-in surface colour: surfaceColor (device-local) tints the flat top bar;
  empty keeps the translucent .bar material. Settings row with an Auto reset.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Calendarr iOS/Views/Calendar/CalendarDrawer.swift

@@ -0,0 +1,151 @@
+import SwiftUI
+
+/// Destinations the drawer can open (presented as sheets by the host).
+enum DrawerDestination: Int, Identifiable {
+    case profile, settings, accounts, groups, server
+    var id: Int { rawValue }
+}
+
+/// The left side drawer: central navigation + calendar visibility + group
+/// switching. Replaces the old menu popup and filter sheet.
+struct CalendarDrawer: View {
+    let api: CalendarrAPI
+    let store: CalendarStore
+    let groups: [CalGroup]
+    let onSwitchGroup: (CalGroup?) -> Void
+    let onSelectView: (CalViewType) -> Void
+    let onOpenDestination: (DrawerDestination) -> Void
+    let onSync: () -> Void
+    let onClose: () -> Void
+
+    @Environment(AppState.self) private var appState
+    @AppStorage("appLanguage") private var appLang = "system"
+
+    var body: some View {
+        VStack(spacing: 0) {
+            header
+            Divider()
+            viewSwitcher
+            if !groups.isEmpty {
+                Divider()
+                groupSwitcher
+            }
+            Divider()
+            CalendarFilterContent(api: api, store: store)
+            Divider()
+            navFooter
+        }
+        .frame(maxWidth: .infinity, maxHeight: .infinity, alignment: .top)
+        .background(Color(.systemBackground))
+    }
+
+    // MARK: – Header
+
+    private var header: some View {
+        HStack(spacing: 12) {
+            Circle()
+                .fill(Color.accentColor)
+                .frame(width: 40, height: 40)
+                .overlay {
+                    Text(appState.username.prefix(1).uppercased())
+                        .font(.headline).foregroundStyle(.white)
+                }
+            VStack(alignment: .leading, spacing: 2) {
+                Text(appState.username).font(.headline).lineLimit(1)
+                Text(appState.serverURL
+                    .replacingOccurrences(of: "https://", with: "")
+                    .replacingOccurrences(of: "http://", with: ""))
+                    .font(.caption).foregroundStyle(.secondary).lineLimit(1)
+            }
+            Spacer()
+            Button { onClose() } label: {
+                Image(systemName: "xmark").font(.system(size: 15, weight: .semibold))
+            }
+            .buttonStyle(.plain).foregroundStyle(.secondary)
+        }
+        .padding(.horizontal, 16).padding(.top, 12).padding(.bottom, 10)
+    }
+
+    // MARK: – View switcher
+
+    private var viewSwitcher: some View {
+        ScrollView(.horizontal, showsIndicators: false) {
+            HStack(spacing: 8) {
+                ForEach(CalViewType.allCases, id: \.self) { vt in
+                    let selected = store.viewType == vt
+                    Button { onSelectView(vt) } label: {
+                        Label(vt.label(appLang), systemImage: vt.systemImage)
+                            .font(.caption.weight(.medium))
+                            .padding(.horizontal, 12).padding(.vertical, 7)
+                            .background(selected ? Color.accentColor : Color(.secondarySystemBackground))
+                            .foregroundStyle(selected ? .white : .primary)
+                            .clipShape(Capsule())
+                    }
+                    .buttonStyle(.plain)
+                }
+            }
+            .padding(.horizontal, 16).padding(.vertical, 8)
+        }
+    }
+
+    // MARK: – Group switcher
+
+    private var groupSwitcher: some View {
+        ScrollView(.horizontal, showsIndicators: false) {
+            HStack(spacing: 8) {
+                chip(label: L10n.t("groups.personal", appLang),
+                     systemImage: "person",
+                     selected: store.activeGroup == nil) { onSwitchGroup(nil) }
+                ForEach(groups) { g in
+                    chip(label: g.name,
+                         systemImage: GroupIcons.symbol(g.icon),
+                         selected: store.activeGroup?.id == g.id) { onSwitchGroup(g) }
+                }
+            }
+            .padding(.horizontal, 16).padding(.vertical, 8)
+        }
+    }
+
+    private func chip(label: String, systemImage: String, selected: Bool, action: @escaping () -> Void) -> some View {
+        Button(action: action) {
+            Label(label, systemImage: systemImage)
+                .font(.caption.weight(.medium))
+                .padding(.horizontal, 12).padding(.vertical, 7)
+                .background(selected ? Color.accentColor : Color(.secondarySystemBackground))
+                .foregroundStyle(selected ? .white : .primary)
+                .clipShape(Capsule())
+        }
+        .buttonStyle(.plain)
+    }
+
+    // MARK: – Nav footer (quick access)
+
+    private var navFooter: some View {
+        ScrollView(.horizontal, showsIndicators: false) {
+            HStack(spacing: 4) {
+                navButton(L10n.t("menu.appearance", appLang), "paintpalette") { onOpenDestination(.settings) }
+                navButton(L10n.t("menu.accounts", appLang), "tray.2") { onOpenDestination(.accounts) }
+                navButton(L10n.t("menu.profile", appLang), "person.circle") { onOpenDestination(.profile) }
+                navButton(L10n.t("groups.title", appLang), "person.2") { onOpenDestination(.groups) }
+                navButton(L10n.t("menu.server", appLang), "server.rack") { onOpenDestination(.server) }
+                navButton(L10n.t("menu.sync", appLang), "arrow.triangle.2.circlepath") { onSync() }
+                navButton(L10n.t("menu.logout", appLang), "rectangle.portrait.and.arrow.right", role: .destructive) {
+                    appState.logout()
+                }
+            }
+            .padding(.horizontal, 12).padding(.vertical, 10)
+        }
+    }
+
+    private func navButton(_ label: String, _ systemImage: String, role: ButtonRole? = nil, action: @escaping () -> Void) -> some View {
+        Button(role: role, action: action) {
+            VStack(spacing: 4) {
+                Image(systemName: systemImage).font(.system(size: 18))
+                Text(label).font(.caption2).lineLimit(1)
+            }
+            .frame(width: 64)
+            .foregroundStyle(role == .destructive ? Color.red : Color.accentColor)
+        }
+        .buttonStyle(.plain)
+    }
+}