build: drop tauri protocol-asset feature (no longer used)

src-tauri/Cargo.toml

@@ -18,7 +18,7 @@ crate-type = ["staticlib", "cdylib", "rlib"]
 tauri-build = { version = "2", features = [] }
 
 [dependencies]
-tauri = { version = "2", features = ["tray-icon", "image-png", "protocol-asset"] }
+tauri = { version = "2", features = ["tray-icon", "image-png"] }
 serde = { version = "1", features = ["derive"] }
 serde_json = "1"
 thiserror = "1"