blogex: CRAP scores as a Lens sensor (ex_crap)

Same wiring as app: `crap` reads the export from `test.coverage`, runs in
MIX_ENV=test, and refuses to score when the export is absent.

Baseline at the default threshold (30): 12 files, 59 functions, worst score
6.00. Nothing to fix; blogex's CRAP ceiling is its coverage ceiling, which the
behavior-test yaks already own.

blogex/Makefile

@@ -3,7 +3,7 @@
 MISE_BIN ?= mise
 MISE_EXEC = $(MISE_BIN) exec --
 
-.PHONY: check precommit deps compile test test.coverage coverage format verify
+.PHONY: check precommit deps compile test test.coverage coverage crap format verify
 
 # Cheap static gate for this library (no database, no coverage). Runs from the
 # root `make check`, which loops app then blogex.
@@ -44,6 +44,20 @@ coverage:
 	@test -f cover/default.coverdata || { echo "coverage: no exported coverage - run 'make test.coverage' first" >&2; exit 1; }
 	$(MISE_EXEC) mix test.coverage
 
+# Enforce CRAP scores (complexity x coverage) from the same export. No test run.
+# Runs in MIX_ENV=test because that is the environment the export came from:
+# running in dev would compile a second build and score against a different set
+# of modules. The guard is load-bearing for the same reason as `coverage`:
+# ex_crap falls back to 0% coverage when the export is missing, which would
+# report scores that are pessimistic instead of absent - a false failure is
+# less bad than a false pass, but neither is acceptable in the Lens pass.
+#
+# Threshold is ex_crap's default (30); whether to ratchet it down is an open
+# decision tracked in the "ratchets, deferred decisions, handoff practice" yak.
+crap:
+	@test -f cover/default.coverdata || { echo "crap: no exported coverage - run 'make test.coverage' first" >&2; exit 1; }
+	MIX_ENV=test $(MISE_EXEC) mix crap
+
 # Format code
 format:
 	$(MISE_EXEC) mix format
@@ -58,6 +72,7 @@ format:
 #   - coverage   (yak: coverage floors + framework-glue exclusions policy)
 #                  WIRED below (test.coverage + coverage).
 #   - crap       (yak: CRAP scores with ex_crap (both apps))
+#                  WIRED below (crap); reuses the coverage export.
 #   - mutation   (yak: mutation testing with muex — a sensor, not a gate)
 #
 # The suite runs FIRST: it is what produces the coverage export that the
@@ -65,7 +80,7 @@ format:
 # `mix test --cover --export-coverage` exports instead of printing a summary,
 # and reporting through `mix test.coverage` keeps it to one suite run.) Sensors
 # still run cheapest-first among themselves.
-VERIFY_SENSORS := coverage
+VERIFY_SENSORS := coverage crap
 
 verify:
 	@echo "==> verify(blogex): suite (coverage exported), then sensors [$(VERIFY_SENSORS)]"