Convert all print statements to SecureLogger

- Replaced all print() calls with appropriate SecureLogger.log() calls
- Used proper categories: noise, encryption, session, security
- Applied appropriate log levels: debug, info, warning, error
- Converted 25 prints in BluetoothMeshService.swift
- Converted 1 print in ChatViewModel.swift
- Converted 8 prints in DeliveryTracker.swift
- Test files kept as-is for debugging purposes
- Verified successful build on iOS

This improves security by using structured logging that can filter sensitive data.

🤖 Generated with [Claude Code](https://claude.ai/code)

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

bitchat/ViewModels/ChatViewModel.swift

@@ -3635,7 +3635,7 @@ extension ChatViewModel: BitchatDelegate {
     }
     
     private func updateMessageDeliveryStatus(_ messageID: String, status: DeliveryStatus) {
-        print("🔄 Updating UI delivery status for message \(messageID): \(status)")
+        SecureLogger.log("Updating UI delivery status for message \(messageID): \(status)", category: SecureLogger.session, level: .debug)
         
         // Helper function to check if we should skip this update
         func shouldSkipUpdate(currentStatus: DeliveryStatus?, newStatus: DeliveryStatus) -> Bool {