fix(scan): generate valid systemd working directory

agents/fedeo-device-agent/scripts/install-linux.sh

@@ -81,7 +81,9 @@ def unit_quote(value):
 unit_path.write_text('\n'.join([
     '[Unit]', 'Description=FEDEO Scan-Agent', 'After=network-online.target', '',
     '[Service]', 'Type=simple',
-    'WorkingDirectory=' + unit_quote(agent_dir),
+    # WorkingDirectory takes a literal path, unlike Environment/ExecStart.
+    # Quotes would become part of the path; only systemd specifiers need escaping.
+    'WorkingDirectory=' + str(agent_dir).replace('%', '%%'),
     'Environment=' + unit_quote('FEDEO_AGENT_ENV=' + str(config_path)),
     'ExecStart=' + unit_quote(node) + ' ' + unit_quote(agent_dir / 'dist/main.js'),
     'Restart=on-failure', 'RestartSec=5', 'UMask=0077', '',