Fixing kiwix restart cmd: missing comma silently concatenated two argv entries.

`cmd = ('sudo', '/usr/bin/systemctl', 'restart' 'wrolpi-kiwix.service')`
                                              ^ missing comma here

Python implicit string-literal concatenation joined the two strings into
'restartwrolpi-kiwix.service', so systemctl saw one argument it didn't
recognise and exited 2 (INVALIDARGUMENT).  Net effect: kiwix never
restarted after a Zim download, the user still had to manually
`sudo systemctl restart wrolpi-kiwix` to see the new Zim.

Adds a unit test that pins the argv shape so an adjacent-literal typo
here surfaces in CI.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

modules/zim/lib.py

@@ -638,7 +638,7 @@ async def restart_kiwix():
 
     logger.info('Restarting Kiwix serve')
 
-    cmd = ('sudo', '/usr/bin/systemctl', 'restart' 'wrolpi-kiwix.service')
+    cmd = ('sudo', '/usr/bin/systemctl', 'restart', 'wrolpi-kiwix.service')
     result = await run_command(cmd)
     logger.debug(f'systemctl returned {result.return_code}')
     if result.return_code != 0 and result.stderr:

modules/zim/test/test_restart_kiwix.py

@@ -1,4 +1,6 @@
 """Tests for the restart_kiwix switch handler triggered by model_zim()."""
+from unittest import mock
+
 import pytest
 
 from modules.zim import lib
@@ -7,6 +9,30 @@ from wrolpi.api_utils import api_app
 from wrolpi.files.models import FileGroup
 
 
+@pytest.mark.asyncio
+async def test_restart_kiwix_systemctl_command_shape():
+    """restart_kiwix() must call systemctl with `restart` and the unit name as
+    separate argv entries.  Adjacent-string-literal typos (missing comma in
+    a Python tuple) silently produce 'restartwrolpi-kiwix.service' as a single
+    argument, which systemctl rejects."""
+    captured = {}
+
+    async def fake_run_command(cmd):
+        captured['cmd'] = cmd
+        return mock.MagicMock(return_code=0, stderr=b'')
+
+    with mock.patch.object(lib, 'PYTEST', False), \
+            mock.patch.object(lib, 'DOCKERIZED', False), \
+            mock.patch.object(lib, 'run_command', side_effect=fake_run_command):
+        await lib.restart_kiwix()
+
+    cmd = captured['cmd']
+    assert 'restart' in cmd
+    assert 'wrolpi-kiwix.service' in cmd
+    # 'restart' and the unit must NOT be concatenated into one argv entry.
+    assert 'restartwrolpi-kiwix.service' not in cmd
+
+
 @pytest.mark.asyncio
 async def test_model_zim_activates_restart_switch(async_client, test_session, zim_path_factory):
     """model_zim() should activate the restart_kiwix switch when creating a new Zim."""