The targeted survey: both probes match, and what p10 proves

HANDOFF-x86-guards.md

@@ -137,6 +137,26 @@ has for the case, and the corpus simply had no program that started a transfer f
 
 `lib/emit.ml`, `lib/check.ml` and `runtime/flan_rt.c` were not modified; no change to any of them was needed.
 
+## The survey
+
+`bash spike/x86/survey.sh p9 p10` — the two new probes, both sides, built and run:
+
+```
+MATCH   2
+DIFFER  0
+REFUSED 0
+```
+
+Worth saying what that second row proves for `p10`, because it is not obvious: the survey hands the compiler an
+**absolute** `$src`, so the location string in the stderr both binaries print is the absolute path, not the
+`spike/x86/…` seen by hand. The two are byte-identical anyway, which is the comparison that matters — a
+hand-encoded backend that got the `.rodata` label or the length register wrong would still exit 134 and would still
+look like a match to anything comparing only exit statuses.
+
+The full run over `test/programs` plus `spike/x86` was in flight beside another lane's and is slow for that reason;
+the number to expect is `HANDOFF-x86-rt.md`'s 97 MATCH plus these two, and the invariant that must hold is 0 DIFFER
+and 0 refused. Before the item-5 fix landed, `p9` was one refusal, which is the shape the invariant exists to catch.
+
 ## What this leaves
 
 Items 1, 2, 3, 6 and 7 of `HANDOFF-x86-rt.md` are untouched and still stand. Two smaller things this lane turned up