fix(786): reconcile the guard-inventory counts after rebasing onto #871

Rebase-only conflict, caught by re-running the gate on the NEW base rather than trusting the green
from the old one. #871 (`docs(796)`) added `scripts/tests/test_mcp_smoke.py` as a MUTATION-graded
guard row while this branch added `scripts/tests/test_workflow_job_guards.py` as another. Each
bumped the hand-maintained summary sentence by one and each was green against its own base; merged,
the table holds 44/22 and the sentence claimed 43/21.

This is `ci.whole-tree-gate-is-only-as-green-as-its-base` — the shape #780 and #784 hit. The
summary is asserted by `test_the_summary_counts_match_the_table`, so it failed loudly rather than
drifting, which is the whole reason that assertion exists.

Refs #786

docs/guard-inventory.md

@@ -355,7 +355,7 @@ clause-provable and the entry is regraded.
 
 ## What the numbers say
 
-43 guards, 6 tooling scripts, 21 proof files. **21 guards carry a mutation proof; 6 are
+44 guards, 6 tooling scripts, 21 proof files. **22 guards carry a mutation proof; 6 are
 behaviour-only; 16 have none.** These figures are asserted against the table by
 `test_the_summary_counts_match_the_table` — they were wrong in the first draft (28/4/6/3/19 against
 a table holding 27/5/6/3/18), because a hand-maintained summary of a table is a second copy of it,