fix: add is_admin() function for Windows builds

The Windows build was failing because ui.rs called crate::is_admin()
but the function didn't exist. Added the implementation using Windows
Security API to check if the process has elevated privileges.

Also added Win32_Security feature to windows crate dependencies.

Cargo.toml

@@ -60,6 +60,7 @@ windows = { version = "0.62", features = [
     "Win32_NetworkManagement_IpHelper",
     "Win32_NetworkManagement_Ndis",
     "Win32_Networking_WinSock",
+    "Win32_Security",
     "Win32_System_LibraryLoader",
     "Win32_System_Threading",
 ] }
@@ -82,6 +83,7 @@ windows = { version = "0.62", features = [
     "Win32_NetworkManagement_IpHelper",
     "Win32_NetworkManagement_Ndis",
     "Win32_Networking_WinSock",
+    "Win32_Security",
     "Win32_System_LibraryLoader",
     "Win32_System_Threading",
 ] }

src/lib.rs

@@ -7,3 +7,41 @@ pub mod config;
 pub mod filter;
 pub mod network;
 pub mod ui;
+
+/// Check if the current process is running with Administrator privileges (Windows only)
+#[cfg(target_os = "windows")]
+pub fn is_admin() -> bool {
+    use windows::Win32::Foundation::HANDLE;
+    use windows::Win32::Security::{GetTokenInformation, TokenElevation, TOKEN_ELEVATION, TOKEN_QUERY};
+    use windows::Win32::System::Threading::{GetCurrentProcess, OpenProcessToken};
+
+    unsafe {
+        let mut token_handle = HANDLE::default();
+
+        // Open the process token
+        if OpenProcessToken(GetCurrentProcess(), TOKEN_QUERY, &mut token_handle).is_err() {
+            return false;
+        }
+
+        let mut elevation = TOKEN_ELEVATION::default();
+        let mut return_length = 0u32;
+
+        // Get the elevation information
+        let result = GetTokenInformation(
+            token_handle,
+            TokenElevation,
+            Some(&mut elevation as *mut _ as *mut _),
+            std::mem::size_of::<TOKEN_ELEVATION>() as u32,
+            &mut return_length,
+        );
+
+        // Close the token handle
+        let _ = windows::Win32::Foundation::CloseHandle(token_handle);
+
+        if result.is_err() {
+            return false;
+        }
+
+        elevation.TokenIsElevated != 0
+    }
+}