Ensure Reliable Video Upload Persistence and Delivery During Background Navigation

Improve the media upload workflow to ensure video messages remain visible and continue uploading reliably when users leave the chat screen or the application enters the background. Currently, if a user sends a video and navigates away from the conversation before the upload completes, the video temporarily disappears from the chat and only reappears once the upload finishes. Additionally, if the user leaves the chat and locks the device during an ongoing upload, the upload may fail entirely, resulting in the video never being delivered to the recipient and not appearing in the conversation afterward. The expected behavior is for pending video messages to persist in the chat with an appropriate uploading state indicator and for uploads to continue or resume reliably across navigation events, app backgrounding, and device lock scenarios. This enhancement would improve message reliability, prevent content loss, and provide a user experience consistent with modern messaging applications.