Fix type inference for non-windows target

server/src/handlers/vision.rs

@@ -428,14 +428,14 @@ pub async fn process_clipboard_snapshot(state: Arc<MemoryState>) {
 
             // Deterministic OCR
             let img_clone = img.clone();
-            let ocr_text_opt = tokio::task::spawn_blocking(move || {
+            let ocr_text_opt: Option<String> = tokio::task::spawn_blocking(move || {
                 #[cfg(target_os = "windows")]
                 {
                     perform_windows_ocr(&img_clone)
                 }
                 #[cfg(not(target_os = "windows"))]
                 {
-                    None
+                    None::<String>
                 }
             })
             .await