fix: use append (>>) instead of overwrite (>) for cron logs and add missing dependencies

- Fixed api/schema.py to generate cron jobs using '>> wecker.log' so logs aren't truncated.
- Added test_bugfix_default_command_uses_append_for_logs in tests/test_api.py to prevent regression.
- Added RPi.GPIO and pygame to pyproject.toml via 'uv add' to fix ModuleNotFoundError in cron jobs.
- Updated README.md to reflect that system python packages are no longer needed.

tests/test_api.py

@@ -40,6 +40,59 @@ def test_auth_invalid():
     assert response.status_code == 401
 
 
+def test_bugfix_default_command_uses_append_for_logs():
+    """
+    Test for bugfix: Ensure the default command appends (>>) to wecker.log
+    instead of overwriting (>) it.
+    """
+    from api.schema import Mutation
+
+    mutation = Mutation()
+    # Call the resolver directly without command to trigger default command generation
+    alarm = mutation.set_alarm(cron_expression="0 9 * * *")
+
+    # Verify the generated command string
+    command = alarm.command
+    assert ">> wecker.log 2>&1" in command, (
+        f"Command must use append '>>' syntax. Got: {command}"
+    )
+    assert "> wecker.log 2>&1" not in command.replace(">> wecker.log", "REPLACED"), (
+        "Command must not use overwrite '>'"
+    )
+
+    # Cleanup
+    mutation.delete_alarm(id=alarm.id)
+
+
+def test_set_alarm_default_command_append():
+    headers = {"X-API-Key": "test-secret"}
+    mutation = """
+    mutation {
+      setAlarm(cronExpression: "0 9 * * *") {
+        id
+        command
+      }
+    }
+    """
+    res = client.post("/graphql", json={"query": mutation}, headers=headers)
+    assert res.status_code == 200
+    data = res.json()["data"]["setAlarm"]
+
+    # Assert the command contains the correct append syntax (>>) and not just overwrite (>)
+    command = data["command"]
+    assert ">> wecker.log 2>&1" in command
+    assert "> wecker.log 2>&1" not in command.replace(">> wecker.log", "REPLACED")
+
+    # Cleanup so we don't break subsequent tests
+    alarm_id = data["id"]
+    mutation_delete = f"""
+    mutation {{
+      deleteAlarm(id: "{alarm_id}")
+    }}
+    """
+    client.post("/graphql", json={"query": mutation_delete}, headers=headers)
+
+
 def test_graphql_workflow():
     headers = {"X-API-Key": "test-secret"}