Chats and Profiles are now distinct, handled as seperate structures at both Memory and DB level, allowing us to create much more complex Chat architectures (Group Chats, etc) with greater ease. Profiles are now more of a metadata side-piece, storing Contact information, while Chats contain all of the communication done throughout Vector.

- Added Header Graphic
- Updated About Section
- Additional Branding Revisions

Update README.md

Fixed a case where OS Badges on MacOS and Windows would work unreliably when Vector was unfocused with a chat open - and also optimised the general Badge flow, reducing Tauri RPC load by handling badges purely in the backend.

Utility functions were created to improve code re-use and to centralise our mime-type-support by reducing redundant cross-codebase mapping.

It's now possible to export your Vector account! The `nsec` is a Nostr-compatible key designed for use in compatible Nostr clients, alternatively, for users that created their account in Vector, you have the prioritised option of a Seed Phrase backup, which is ideal for portable offline storage or airgapped storage.

Previously, Vector's DB versioning handling was all over the codebase, making it incredibly difficult to maintain and causing some non-sequential upgrade bugs to slip through, now, Vector's DB upgrades are handled in proper sequential ordering, with guarenteed `dbver` updates - cleaner, safer, and significantly easier to maintain and extend functionally.

Mutes weren't properly applying after the state split, this unifies them functionally, with futureproofing for non-DM-chats, too.

Similar to Android's video handling, Voice Messages and Audio were being 'cut off' early due to a lack of Range Requests in Tauri's asset protocol; for now, we'll simply preload the entire asset in to memory.