fix: restore app_name variable and add Linux X11 build dependencies

Two issues were preventing cross-platform builds:
1. app_name variable was removed during v0.4.15 migration but code still uses it on macOS/Windows
2. Linux workflow was missing X11 development library installation causing build failure

This restores the app_name variable and adds libx11-dev and related packages to the Linux build step.

Author: adolfousier

.github/workflows/build-executables.yml

@@ -1,13 +1,15 @@
 name: Build Cross-Platform Executables
 
 on:
+  push:
+    branches: [main]
   release:
     types: [created]
   workflow_dispatch:
     inputs:
       release_tag:
         description: 'Release tag (e.g., v0.4.15)'
-        required: true
+        required: false
 
 permissions:
   contents: write
@@ -18,6 +20,9 @@ jobs:
     steps:
       - uses: actions/checkout@v4
 
+      - name: Install dependencies
+        run: sudo apt-get update && sudo apt-get install -y xorg-dev
+
       - name: Install Rust
         uses: dtolnay/rust-toolchain@stable
 

src/tracker/monitor.rs

@@ -201,6 +201,7 @@ impl AppMonitor {
             match get_active_window() {
                 Ok(active_window) => {
                     let mut title = active_window.title.clone();
+                    let app_name = active_window.app_name.clone();
 
                     #[cfg(target_os = "macos")]
                     {