fix: Conditionally compile systemd features for Linux only

Co-authored-by: aider (gemini/gemini-2.5-pro-preview-05-06) <aider@aider.chat>

setup.sh

@@ -28,11 +28,15 @@ sudo ln -sf $INSTALL_DIR/timeturner $BIN_DIR/timeturner
 echo "✅ Binary installed to $INSTALL_DIR and linked to $BIN_DIR."
 
 # 4. Install systemd service file
-echo "⚙️  Installing systemd service..."
-sudo cp timeturner.service /etc/systemd/system/
-sudo systemctl daemon-reload
-sudo systemctl enable timeturner.service
-echo "✅ Systemd service installed and enabled."
+if [[ "$(uname)" == "Linux" ]]; then
+    echo "⚙️  Installing systemd service for Linux..."
+    sudo cp timeturner.service /etc/systemd/system/
+    sudo systemctl daemon-reload
+    sudo systemctl enable timeturner.service
+    echo "✅ Systemd service installed and enabled."
+else
+    echo "⚠️  Skipping systemd service installation on non-Linux OS."
+fi
 
 echo ""
 echo "--- Setup Complete ---"
@@ -40,12 +44,14 @@ echo "The TimeTurner daemon is now installed."
 echo "The working directory is $INSTALL_DIR."
 echo "A default 'config.yml' will be created there on first run."
 echo ""
-echo "To start the service, run:"
-echo "  sudo systemctl start timeturner.service"
-echo ""
-echo "To view live logs, run:"
-echo "  journalctl -u timeturner.service -f"
-echo ""
+if [[ "$(uname)" == "Linux" ]]; then
+    echo "To start the service, run:"
+    echo "  sudo systemctl start timeturner.service"
+    echo ""
+    echo "To view live logs, run:"
+    echo "  journalctl -u timeturner.service -f"
+    echo ""
+fi
 echo "To run the interactive TUI instead, simply run from the project directory:"
 echo "  cargo run"
 echo "Or from anywhere after installation:"