fix: ensure single_instance works

https://github.com/WLBF/single-instance#ensuring-the-singleinstance-stays-during-lifetime-of-the-process

src/ui/single_instance.rs

@@ -3,16 +3,19 @@ use single_instance::SingleInstance;
 use std::process;
 
 pub fn single_instance() {
-    let instance = SingleInstance::new("hyprdim").unwrap();
+    let instance = Box::new(SingleInstance::new("hyprdim").unwrap());
 
-    // Don't allow more than one hyprdim instance to run
-    if !instance.is_single() {
-        println!(
-            "hyprdim is already running. Use `killall hyprdim` to stop any existing processes."
-        );
+    if instance.is_single() {
+        Box::leak(instance);
 
-        process::exit(1);
-    };
+        log("hyprdim is now running.");
 
-    log("hyprdim is now running.");
+        return;
+    }
+
+    println!(
+        "hyprdim is already running. Use `killall hyprdim` to stop any existing processes."
+    );
+
+    process::exit(1);
 }