[codex] Refactor app runtime and ownership architecture (#1104)

* Refactor app runtime and view model architecture

* Move app ownership into stores and coordinators

* Fix smoke test environment injection

* Stabilize fragmentation package tests

* Fix coordinator build warnings

* Clean up chat view model warnings

* Fix Nostr relay startup coalescing

---------

Co-authored-by: jack <jackjackbits@users.noreply.github.com>

bitchat/ViewModels/ChatDeliveryCoordinator.swift

@@ -0,0 +1,89 @@
+import BitFoundation
+import BitLogger
+import Foundation
+
+final class ChatDeliveryCoordinator {
+    private unowned let viewModel: ChatViewModel
+
+    init(viewModel: ChatViewModel) {
+        self.viewModel = viewModel
+    }
+
+    @MainActor
+    func cleanupOldReadReceipts() {
+        guard !viewModel.isStartupPhase, !viewModel.privateChats.isEmpty else {
+            return
+        }
+
+        let validMessageIDs = Set(
+            viewModel.privateChats.values.flatMap { messages in
+                messages.map(\.id)
+            }
+        )
+
+        let oldCount = viewModel.sentReadReceipts.count
+        viewModel.sentReadReceipts = viewModel.sentReadReceipts.intersection(validMessageIDs)
+
+        let removedCount = oldCount - viewModel.sentReadReceipts.count
+        if removedCount > 0 {
+            SecureLogger.debug("🧹 Cleaned up \(removedCount) old read receipts", category: .session)
+        }
+    }
+
+    @MainActor
+    func didReceiveReadReceipt(_ receipt: ReadReceipt) {
+        updateMessageDeliveryStatus(
+            receipt.originalMessageID,
+            status: .read(by: receipt.readerNickname, at: receipt.timestamp)
+        )
+    }
+
+    @MainActor
+    func didUpdateMessageDeliveryStatus(_ messageID: String, status: DeliveryStatus) {
+        updateMessageDeliveryStatus(messageID, status: status)
+    }
+
+    @MainActor
+    func updateMessageDeliveryStatus(_ messageID: String, status: DeliveryStatus) {
+        var didUpdateStatus = false
+
+        if let index = viewModel.messages.firstIndex(where: { $0.id == messageID }) {
+            let currentStatus = viewModel.messages[index].deliveryStatus
+            if !shouldSkipUpdate(currentStatus: currentStatus, newStatus: status) {
+                viewModel.messages[index].deliveryStatus = status
+                didUpdateStatus = true
+            }
+        }
+
+        var privateChats = viewModel.privateChats
+        for (peerID, chatMessages) in privateChats {
+            guard let index = chatMessages.firstIndex(where: { $0.id == messageID }) else { continue }
+
+            let currentStatus = chatMessages[index].deliveryStatus
+            guard !shouldSkipUpdate(currentStatus: currentStatus, newStatus: status) else { continue }
+
+            let updatedMessages = chatMessages
+            updatedMessages[index].deliveryStatus = status
+            privateChats[peerID] = updatedMessages
+            didUpdateStatus = true
+        }
+
+        if didUpdateStatus {
+            viewModel.privateChats = privateChats
+            viewModel.objectWillChange.send()
+        }
+    }
+}
+
+private extension ChatDeliveryCoordinator {
+    func shouldSkipUpdate(currentStatus: DeliveryStatus?, newStatus: DeliveryStatus) -> Bool {
+        guard let currentStatus else { return false }
+
+        switch (currentStatus, newStatus) {
+        case (.read, .delivered), (.read, .sent):
+            return true
+        default:
+            return false
+        }
+    }
+}