Add Tauri app backend setup with dependencies and basic build script

- Introduced `build.rs` for Tauri build process initialization.
- Added `Cargo.toml` with dependencies for Tauri plugins, serialization, cryptography, and database handling.
- Generated `Cargo.lock` to lock package versions for consistency.

src-tauri/gen/schemas/capabilities.json

@@ -0,0 +1 @@
+{"default":{"identifier":"default","description":"Default capabilities for the main and login windows","local":true,"windows":["main","login"],"permissions":["core:default","core:window:allow-create","core:window:allow-close","core:window:allow-show","core:window:allow-hide","core:window:allow-set-focus","core:window:allow-center","core:webview:allow-create-webview-window","shell:allow-open","updater:default","process:allow-restart",{"identifier":"http:default","allow":[{"url":"https://api.eritors.com/**"},{"url":"https://scribe.eritors.com/**"},{"url":"https://eritors.com/**"}]}]}}