feat(release): add per-commit backport audit

Backport labels record requests, and a merged conflict draft may still
lack commits. Release cuts need a check of what reached the branch.

Signed-off-by: Myasnikov Daniil <myasnikovdaniil2001@gmail.com>
Assisted-by: LLM

.gitignore

@@ -11,6 +11,7 @@ _repos
 # root-level binary waiting to happen — each ~80 MB, and nothing else here
 # matched them, leaving `git add .` one keystroke from committing one.
 /api-gate
+/backport-audit
 /backup-controller
 /backupstrategy-controller
 /check-readiness

Makefile

@@ -1,4 +1,4 @@
-.PHONY: manifests assets prepare-env prepare-env-container unit-tests helm-unit-tests bats-unit-tests bats-unit-files-check rd-presets-check migrations-target-check test test-controllers preflight
+.PHONY: manifests assets prepare-env prepare-env-container unit-tests helm-unit-tests bats-unit-tests bats-unit-files-check rd-presets-check migrations-target-check test test-controllers test-backport-audit preflight
 
 # Before any include, the last file make has read is this one: MAKEFILES and
 # -f files given before it are earlier in the list, -f files after it are not
@@ -123,7 +123,7 @@ test:
 	make -C packages/core/testing apply
 	make -C packages/core/testing e2e
 
-unit-tests: helm-unit-tests bats-unit-tests go-unit-tests go-module-tests rd-presets-check test-check-readiness migrations-target-check
+unit-tests: helm-unit-tests bats-unit-tests go-unit-tests go-module-tests rd-presets-check test-check-readiness test-backport-audit migrations-target-check
 
 helm-unit-tests:
 	hack/helm-unit-tests.sh
@@ -175,6 +175,10 @@ test-controllers:
 test-check-readiness:
 	go test ./test/check-readiness/ -count=1
 
+# ./cmd/... is excluded from go-unit-tests, so the audit needs its own target.
+test-backport-audit:
+	go test ./cmd/backport-audit/ -count=1
+
 # Discover every hack/*.bats file that is NOT an e2e test and run it
 # through cozytest.sh. This glob is one level deep: live-cluster suites under
 # hack/e2e-* or in subdirectories need an invocation in packages/core/testing.