feat: freeze typed metrics registry and bounded exemplars

scripts/check-rust-module-boundaries.sh

@@ -22,6 +22,7 @@ echo "Rust module boundary check: checking module-level imports"
 
 python3 "$ROOT_DIR/scripts/check-config-boundaries.py" --root "$ROOT_DIR" || status=1
 python3 "$ROOT_DIR/scripts/check-migration-boundaries.py" --root "$ROOT_DIR" || status=1
+python3 "$ROOT_DIR/scripts/check-metrics-boundaries.py" --root "$ROOT_DIR" || status=1
 
 check_no_match \
   "admin-api service modules must not depend on axum HTTP types" \
@@ -50,13 +51,6 @@ check_no_match \
   '^\s*use\s+(axum|sqlx)(::|[;\{])' \
   "$ROOT_DIR/crates/crank-runtime/src"
 
-check_no_match \
-  "product modules must record metrics only through crank-metrics" \
-  '(^|[^[:alnum:]_])(::)?metrics::(counter|gauge|histogram)!' \
-  "$ROOT_DIR/apps" \
-  "$ROOT_DIR/crates" \
-  --glob '!**/crank-metrics/**'
-
 if (( status != 0 )); then
   cat >&2 <<'EOF'