docs: record checker format gate

.scratch/saas-production-readiness/issues/08-prove-production-release-gate.md

@@ -2,7 +2,7 @@
 
 Type: task
 Status: open
-Blocked by: 01, 02, 03, 04, 05, 06, 07
+Blocked by: 01, 02, 03, 04, 05, 06, 07, 09
 
 ## Question
 

.scratch/saas-production-readiness/issues/09-restore-checker-format-gate.md

@@ -0,0 +1,11 @@
+# Restore the checker formatting gate
+
+Type: task
+Status: open
+
+## Question
+
+Apply the repository's configured rustfmt output to the currently reported
+Rust files, verify that no semantic changes are introduced, and restore
+`cargo fmt --all --check` so the checker CI gate is green.
+