Enable system group functionalities

[renner]

This patch is enabling some system group related functionalities, so far:

• List all system groups visible to the user
• Create new system groups
• List systems assigned to a group
• Add and remove systems from groups

[cbbayburt]

Thanks for the PR, @renner.

I think the next tool to add would be list_sysyems_in_group. For the other end of the relation, I'll add a system_groups attribute to get_system_details tool so the LLM can figure out the connection.

I think for now, these 2 tools would be sufficient. For later, we can consider adding/removing systems to groups, or managing groups, but since they're not daily/repeat operations, I wouldn't clutter the toolset with them for now.

Just one suggestion for docstring tool descriptions moving forward:

Between the current Returns: paragraphs and the following, I found out that the following works better:

async def get_system_details(system_identifier: Union[str, int], ctx: Context):
    """Gets details of the specified system.

    Args:
        system_identifier: The system name (e.g., "buildhost.example.com") or system ID (e.g., 1000010000).
        Prefer using numerical system IDs instead of system names when possible.
    Returns:
        An object that contains the following attributes of the system:
            - system_id: The numerical ID of the system within Uyuni server
            - system_name: The registered system name, usually its main FQDN
            - last_boot: The last boot time of the system known to Uyuni server
            - uuid: UUID of the system if it is a virtual instance, null otherwise.
            - cpu: An object with the following CPU attributes of the system:
                - family: The CPU family
                - mhz: The CPU clock speed
                - model: The CPU model
                - vendor: The CPU vendor
                - arch: The CPU architecture
            - installed_product: List of installed products on the system.
              You can use this field to identify what OS the system is running.

        An empty object is returned if the system cannot be found.

        Example:
            {
              "system_id": "100010001",
              "system_name": "opensuse.example.local",
              "last_boot": "2025-04-01T15:21:56Z",
              "uuid": "a8c3f40d-c1ae-406e-9f9b-96e7d5fdf5a3",
              "cpu": {
                "family": "15",
                "mhz": "1896.436",
                "model": "QEMU Virtual CPU",
                "vendor": "AuthenticAMD",
                "arch": "x86_64"
              }
            }
        """

Python type definitions don't make any sense to the LLM, because what it'll see is just JSON. So, for the "Returns:" clause, one clear natural language description including its attributes, followed by a clear JSON example works best.

[renner]

Thanks @cbbayburt, I added a commit to improve the Return: part of the docstring tool descriptions. Hope it looks good now. I might add some additional test cases, so far only group creation is covered.

[ycedres]

LGTM. Also tested the changed test cases file and runs ok.