feat: add Helium Browser cleanup support

Add cleanup support for Helium Browser (Chromium-based) on macOS.

Helium paths added:
- ~/Library/Caches/net.imput.helium/*
- ~/Library/Application Support/net.imput.helium/*/GPUCache/*
- ~/Library/Application Support/net.imput.helium/component_crx_cache/*
- ~/Library/Application Support/net.imput.helium/extensions_crx_cache/*
- ~/Library/Application Support/net.imput.helium/GrShaderCache/*
- ~/Library/Application Support/net.imput.helium/GraphiteDawnCache/*
- ~/Library/Application Support/net.imput.helium/ShaderCache/*
- ~/Library/Application Support/net.imput.helium/*/Application Cache/*

Also added "Helium" to the browser process detection list in optimize/tasks.sh.

Closes #534

lib/optimize/tasks.sh

@@ -475,6 +475,7 @@ opt_font_cache_rebuild() {
             "Opera"
             "Vivaldi"
             "Zen Browser"
+            "Helium"
         )
         for browser_name in "${browser_checks[@]}"; do
             if pgrep -ix "$browser_name" > /dev/null 2>&1; then