bug: cardinal/signed 32-bit expression width (orphan addendum)

• Type: bug (Track A — type promotion / codegen width)
• Status: DONE 2026-06-23 (both halves resolved elsewhere)
• Found: 2026-06-23, differential probe vs FPC

This file was an orphaned addendum fragment. Both parts are fixed and tracked by their own done tickets:

1. Cardinal/LongWord binary-op → uint64 (FPC: int64). Resolved — see done/bug-cardinal-expr-promotion.md (TypeArithmeticResult only widens to uint64 for a genuinely 64-bit unsigned operand).

2. Signed 32-bit shr widened to 64-bit (the "## Also" addendum that lived here: Integer(-8) shr 1 gave a 64-bit value). Resolved — see done/bug-shr-signed-integer-width.md (commit 346a26f: shr at operand width on x86-64 + aarch64). Re-verified 2026-06-23 vs FPC {$mode objfpc}: i shr 1, c shr 1, l shr 1, i shr 28 all match.

Closed to clear the backlog stub; no remaining work.