docs: adopt the reviewed wordings for the restored scopes

[velzepooz]

A tail of #33 that missed the merge. Same rule, four small edits, no new ground.

#33 removed measurements and defeat recipes from comments and prose while keeping the reasoning that stops someone widening a deliberately narrow predicate. In eleven places its first pass had turned a bounded measurement into a universal claim — "0 malicious hits on the bench corpus" becoming "does not appear in hostile ones" — and those were re-bounded before merge. This adopts the reviewed wordings for four of them and fixes two paragraphs that reflowed badly.

Where	Was	Now
pkg/rules/access_control.go	"no hostile sample in the validation corpus carried it"	"was not seen on the hostile side, which is what earns it an exemption"
adversarial_test.go (two why: strings)	"not seen on the hostile side of the validation corpus"	"not seen on the hostile side"
CHANGELOG.md SD-007 entry	"a chained URL-plus-reverse-shell statement graded security A"	"a reverse shell chained after an echo graded security A, while the identical line in a run.sh graded D"
CHANGELOG.md	"the headline results held"	"few enough not to move the entry above"

The changelog one is the only edit with substance: the merged wording had blurred what the rule actually forgot, and this restores both the defect and the two grades that show it, without the worked payload that was removed in #33.

Also rewrapped two paragraphs that #33 left with orphan tails.

Verification

• Four non-comment changed lines, both halves of the two why: strings in adversarial_test.go. That field is read only as a t.Errorf format argument, so the change is behaviour-neutral by construction.
• go test ./... — 1085 tests, 12 packages, green.
• CHANGELOG.md unchanged structurally against main: 13 version headings, 67 entry bullets, every grade-changing warning present.
• The worked reverse-shell payload and the covert-channel recipe removed in docs: stop the source disclosing what the docs withhold #33 are both still absent; the surviving nc -e mentions are the bare technique name in prose, which the rule's own entry has always named.

https://claude.ai/code/session_01XAY7LzfeuEZBgSLuzpWUAH