kb: refusal no longer offers committing the loss; skill and kb-tool.md describe the guard (improvise-za97)

The kb skill (both copies) now describes the HEAD comparison, the ledger,
exit code 3 and the recovery. kb-tool.md records the ih3k/yea8 arguments and
corrects the residue paragraph: .gitignore hides the leftovers, and there are
six, not one.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01VdfEGXA7aJ6ftMsCc9PJze

scripts/kb-test.sh

@@ -553,6 +553,17 @@ else
   bad "the truncation was refused, but not by the completeness guard"
 fi
 
+# 19b. ...and the refusal must not offer committing the loss as the way out:
+#      a committed loss becomes the floor, and is never reported again
+#      (improvise-za97).
+if said "$work/out" "commit the removal"; then
+  bad "the refusal still offers committing an unexplained loss"
+elif said "$work/out" "do NOT commit"; then
+  ok "the refusal warns against committing the loss"
+else
+  bad "the refusal says nothing about committing the short kb"
+fi
+
 # 20. rm is how the count legitimately falls, and the ledger is how a LATER
 #     write knows it: rm a clause HEAD has, then add -- the add must land. A
 #     ledger that is never written, or is ignored, refuses here.