Add rustfmt.toml (same as core and server) and apply cargo fmt

Formatting only. CI now runs cargo fmt --check here as in the other Rust repos.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

src-tauri/src/ipc.rs

@@ -389,15 +389,7 @@ mod imp {
         let name = wide(&pipe_name());
         // SAFETY: name is NUL-terminated; the handle is owned by File on success.
         let h = unsafe {
-            CreateFileW(
-                name.as_ptr(),
-                GENERIC_READ | GENERIC_WRITE,
-                0,
-                ptr::null(),
-                OPEN_EXISTING,
-                0,
-                ptr::null_mut(),
-            )
+            CreateFileW(name.as_ptr(), GENERIC_READ | GENERIC_WRITE, 0, ptr::null(), OPEN_EXISTING, 0, ptr::null_mut())
         };
         if h == INVALID_HANDLE_VALUE {
             return Err(io::Error::last_os_error());