Partial reload `only` option behavior with lazy, deferred, and shared props

Goal: determine whether the `only` filter applied during a partial reload also limits shared middleware data and whether lazy or deferred props are treated as already requested when omitted from `only`.

Constraints: the `only` option is scoped to a single request, does not persist across full navigations, and its interaction with lazy props (evaluated on demand) and deferred props (auto‑triggered partial reload after initial render) is not explicitly defined in the current documentation, making the behavior version‑sensitive between Inertia 1 and Inertia 2.

Questions: Does specifying `only` exclude shared middleware props from the response, or are they always included regardless of the filter? When a lazy prop is omitted from `only`, does the client retain its previous value or remain undefined? If a deferred prop is scheduled but not listed in `only`, does the automatic partial reload still occur, and how does that affect the prop’s availability on the page?