Fix arm-deployments split SDK client

[TacoRocket]

Summary

• switch arm-deployments to the split Azure deployments management client introduced by the current azure-mgmt-resource package
• add the new default dependency so editable installs include the runtime client automatically
• add regression coverage for both the client factory and the arm-deployments collector path

Root cause

azure-mgmt-resource 25.0.0 moved deployment operations off ResourceManagementClient into DeploymentsMgmtClient from azure-mgmt-resource-deployments. AzureFox had already absorbed the subscriptions split, but arm-deployments was still calling self.clients.resource.deployments, which now raises 'ResourceManagementClient' object has no attribute 'deployments' and empties the command output.

Verification

• ruff check src/azurefox/clients/factory.py src/azurefox/collectors/provider.py tests/test_clients_factory.py tests/test_collectors.py
• pytest tests/test_clients_factory.py tests/test_collectors.py -q
• AZURE_CONFIG_DIR=/tmp/azurefox-azure-config PYTHONPATH='/Users/cfarley/Documents/HarrierOps/Azure/Family AF/AzureFox/src' /tmp/azurefox-runtime-compat-venv/bin/python -m azurefox --subscription b436881a-b87e-44b6-a5d6-7bf7f4bc9c88 --output json arm-deployments
• repo pre-push guardrail: PYTHONPATH=src python3 -m pytest -m "not integration" -> 413 passed, 2 deselected

Note

• repo-preferred clean-context CCR was not run because this session does not permit subagent delegation unless explicitly requested