Preserve captured HighC loads across memory assignments

[gmh5225]

Summary

• Fix a statically demonstrated HighC miscompile: an Assign statement with a Load destination writes memory, but the value-forwarding clobber check did not recognize it.
• Route that write form through the existing address/overlap policy, using the destination access width.
• Add HighValueForward.SlotLoadStaysBeforeAnAssignmentToItsSlot to the already-registered NeverDHighControlFlowTests target.
• Refresh only English PROGRESS.md; preserve the complete previous 135,547-character tracker verbatim.

Static evidence

The sequence store(slot, x); t1 = load(slot); assign(load(slot), 5); return t1 could fold the captured load past the overwrite. Existing statement emission supports this write form; earlier immutable-slot forwarding refuses it and liveness retains it. The fix preserves the original captured value and does not change shared IR or LLVMC.

Code commit: a6468b8.
Report commit: 550608a.
Reviewed dev range: 6f885eb → db18af3.
Inventory: 198 commits / 557 paths; 196 / 556 excluding the two report-only commits and PROGRESS path. This is not exhaustive audit coverage.

Verification and limits

Strictly static. No project execution, build, test, benchmark, repository script, formatter/linter or CI dispatch/rerun.
The new regression declares emitted-C checks at O0/O2 using the existing helper; it has not been executed. No compilation/runtime/formatting pass is claimed.
Remote source/test readbacks equal intended content. The code commit changes exactly two files, 26 additions/3 deletions; its remote diff was inspected. Report readback is exact and preserves all prior history; its separate commit changes only PROGRESS.md with zero deleted lines.

Existing qualification blockers

At October 7 01:01:56 UTC, pinned dev has 19 checks: four success, two failure, three running, ten skipped. Linux cannot compile four Darwin initializer lists; all four repairs already exist in unmerged #589, whose default Linux build passed but later Mach-O tests failed. No duplicate patch is included.
Pinned dev mobile macOS fails on unsupported preprocessor directives, and all real-application jobs are skipped. Existing #605 has failed remote CI and mergeability false. Local author reports remain separate from remote results.
The full report records exact heads, jobs, sample times, missing-test denominators, open work and bounded next priorities.

No other documentation, dependency, security setting, issue state, merge or deployment changed. No CI-skip markers; ordinary automatic checks may run. This draft does not authorize merging.