fix: gate deauth_directional to Linux

The non-Linux stub at the bottom of the file duplicated a definition that had
no #[cfg(target_os = "linux")] of its own — it inherited none from the
unrelated #[allow] above it. Every non-Linux build (the desktop app's Windows
CI job included) failed with a duplicate-definition error and unresolved
Linux-only imports inside the always-compiled body.

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

crates/sabia-core/src/engine.rs

@@ -1198,6 +1198,7 @@ impl Engine {
 
     /// `direction`: `ap` (AP→STA), `sta` (STA→AP, exige estação) ou `both`.
     /// `frame_kind`: `deauth` ou `disassoc`.
+    #[cfg(target_os = "linux")]
     #[allow(clippy::too_many_arguments)]
     pub fn deauth_directional(
         &self,