Gate Docker CLI resolution behind Enable in OnInitForSite

[mirkobrombin]

Docker CLI resolution should only be initialized when explicitly enabled via the Enable setting in OnInitForSite.

Current behavior

Docker CLI is resolved unconditionally during site initialization.

Expected behavior

Docker CLI resolution should be gated behind an enable flag to prevent unnecessary initialization and potential errors when Docker is not required or available.

Implementation

Update OnInitForSite to check the Enable setting before resolving Docker CLI dependencies.