Merge claude/strange-mirzakhani-179c4e (design-alignment rewrite)

# Conflicts:
#	swift/Assets.xcassets/LaneFeed.colorset/Contents.json
#	swift/Assets.xcassets/LanePaper.colorset/Contents.json
#	swift/Assets.xcassets/LanePeople.colorset/Contents.json
#	swift/Assets.xcassets/SIOTint.colorset/Contents.json
#	swift/SocialIO.xcodeproj/project.pbxproj
#	swift/Sources/App/SocialIOApp.swift
#	swift/Sources/Core/Models/MailModels.swift
#	swift/Sources/Core/Services/MockMailService.swift
#	swift/Sources/Features/Mail/MailRootView.swift

swift/Sources/App/AppViewModel.swift

@@ -5,6 +5,7 @@ import Observation
 @Observable
 final class AppViewModel {
     var selectedMailbox: Mailbox = .inbox
+    var selectedLane: Lane?
     var selectedThreadID: MailThread.ID?
     var focusedMessageRouteID: String?
     var searchText = ""
@@ -50,6 +51,10 @@ final class AppViewModel {
             .filter { thread in
                 laneFilter == nil || thread.lane == laneFilter
             }
+            .filter { thread in
+                guard let lane = selectedLane else { return true }
+                return thread.lane == lane
+            }
             .filter { thread in
                 !showUnreadOnly || thread.isUnread
             }
@@ -57,6 +62,27 @@ final class AppViewModel {
             .sorted { $0.lastUpdated > $1.lastUpdated }
     }
 
+    func laneUnreadCount(_ lane: Lane) -> Int {
+        threads.filter { thread in
+            let inCurrentMailbox = selectedMailbox == .starred
+                ? thread.isStarred
+                : thread.mailbox == selectedMailbox
+            return inCurrentMailbox && thread.lane == lane && thread.isUnread
+        }.count
+    }
+
+    func laneThreadCount(_ lane: Lane) -> Int {
+        threads.filter { thread in
+            thread.mailbox == .inbox && thread.lane == lane
+        }.count
+    }
+
+    func selectLane(_ lane: Lane?) {
+        selectedLane = lane
+        clearThreadSelection()
+        mailboxNavigationToken = UUID()
+    }
+
     var totalUnreadCount: Int {
         threads.filter(\.isUnread).count
     }