Parenthesize upcast when inlining a Use= mapping in a queryable projection

Description

A queryable projection that inlines a Use= helper whose parameter is a supertype (interface or base class) of the projected source element generated an upcast without parentheses:

// source: x => new Target { Result = MapResult((IBase)x) }, inlined to:
Result = (IBase)x.Value      // Parses as (IBase)(x.Value)

Because a parameter identifier binds tighter than a member-access receiver, dropping the helper's body inline reattaches the cast to the wrong subtree. The result either fails to compile or binds the wrong member.

The inliner now parenthesizes a substituted cast when it lands in a receiver position:

Result = ((IBase)x).Value    // Correct

Fixes #2340

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