A bare CLR-only annotation resolves but emits an unqualified name: SPY0908 CS0246 (the non-generic half of #1765) #1830

Measured on branch v5/clr-resolution (P4 remediation R5) and present at 311252e33.

def take(sb: StringBuilder) -> str:
    return sb.to_string()

def main() -> None:
    print("ok")

error[SPY0908]: internal error: generated C# failed to compile
  (CS0246: The type or namespace name 'StringBuilder' could not be found ...)

Emitted:

public static string Take(StringBuilder sb)

Class

BuiltinRegistry.TryResolveClrType resolves a bare type name through its namespace list with no import at all, so the annotation type-checks. The emitter then names it from the symbol: TypeSyntaxMapper.GetMappedTypeNameFromSymbol routes a CLR-backed symbol through the qualification authority only when ClrType is { IsGenericType: true }, so a non-generic CLR-fallback type falls through to the short-name path and binds only if a using in the prelude happens to cover its namespace. List[int] looked fine for the same reason (using System.Collections.Generic); System.Text is not in the prelude, so StringBuilder is a hard SPY0908.

This is the non-generic half of #1765's "every CLR-backed type is named from its reflected type" contract. #1765's generic half is fixed on v5/clr-resolution (the registry entries for IEnumerable/IEnumerator now name the open generic definitions and the !typeSymbol.IsGeneric carve-out is gone), which is what made this half visible as a matrix hole.

Cells

ClrTypeResolutionPriorityTests (new, src/Sharpy.Compiler.Tests/Semantic/) covers kind {Sharpy-only, collision, CLR-only} x spelling {bare, imported, module-qualified, aliased, backtick}. The ClrOnly x bare cell is the only one carried as a [Fact(Skip = ...)] citing this issue; imported / module-qualified / aliased all run. Deleting the Skip is this issue's acceptance.

Either widen the qualification gate to every non-Sharpy ClrType (the seam is GetMappedTypeNameFromSymbol, one condition), or refuse a bare CLR name with no import by name instead of resolving it. Whichever is chosen, the fix is one predicate, not a per-namespace using list.