feat(browser): integrate Zen Browser into install script and documentation

install.sh

@@ -205,6 +205,42 @@ install_1password_cli() {
     esac
 }
 
+install_zen_browser() {
+    log "Installing Zen Browser..."
+    
+    case $OS in
+        "macos")
+            if [ -d "/Applications/Zen.app" ] || [ -d "$HOME/Applications/Zen.app" ]; then
+                log "Zen Browser is already installed."
+                return
+            fi
+            install_cask zen
+            ;;
+        "arch")
+            if command -v zen-browser &> /dev/null; then
+                log "Zen Browser is already installed."
+                return
+            fi
+            if command -v yay &> /dev/null; then
+                yay -S --noconfirm zen-browser-bin
+            else
+                warn "yay not found, cannot install zen-browser-bin on Arch"
+            fi
+            ;;
+        "debian"|"fedora")
+            if command -v zen-browser &> /dev/null; then
+                log "Zen Browser is already installed."
+                return
+            fi
+            if command -v flatpak &> /dev/null; then
+                flatpak install -y flathub io.github.zen_browser.zen || true
+            else
+                warn "Zen Browser needs Flatpak or manual installation on $OS (https://zen-browser.app)"
+            fi
+            ;;
+    esac
+}
+
 install_core_tools() {
     log "Installing core development tools..."
     
@@ -291,6 +327,7 @@ install_core_tools() {
     esac
     
     install_1password_cli
+    install_zen_browser
     
     log "Core tools installed!"
 }