{$Q+} narrow-width overflow still unchecked on the 32-bit backends

Follow-up to bug-a-qplus-misses-32bit-overflow (fixed on x86-64 + aarch64 at the narrowing store: a Q-tagged binop feeding a sub-64-bit ordinal store now range-checks the exact wide result against the destination width).

Still open: i386 / arm32 / riscv32 / xtensa. Confirmed on i386: the 32-bit-overflow repro prints -294967296 and exits 0 — despite Integer being "native width" there, the arithmetic evidently runs wide (ILP32 64-bit = register pair; see project_32bit_truthiness_and_promotion_landmines) or the tag never reaches the emitted op. SmallInt/Byte/Cardinal narrows are unchecked there too.

Fix shape: mirror the store-site range check per backend (the exact-wide-value

• re-extend + compare pattern in ir_codegen.inc EmitOvfCheckNarrowX64 / the aarch64 IR_STORE_SYM hook). Measure first per backend whether the tag is (a) absent, (b) skipped, or (c) width-blind, as the parent ticket insisted.

Gate: test/test_overflow_qplus_narrow.pas prints caught=5 clean=4 wrap=-294967296 on each backend; wire it into the four cross suites next to test_overflow_checks_qplus.pas.

Log

• 2026-07-22 — resolved, commit 9097042d.