Allow SharedVariables Livewire components (Environment, Project, Server)
to accept UUID parameters directly via mount() instead of relying solely
on route parameters. This enables Livewire component testing without a
live route context.
Also adds comment field support when saving/updating server shared
environment variables, guards PostgreSQL-specific migration statements
from running under SQLite (test environment compatibility), and expands
the feature test suite with server shared variable scenarios including
inline comment preservation and update behaviour.
