Deny vaultik's faultstore package to non-test code in depguard

The canonical config asks each repo to name its own test-support
packages in the depguard test-support deny list. faultstore is one
and its directory name does not end in test.

Model: opus-5-5

.golangci.yml

@@ -60,6 +60,10 @@ linters:
               desc: >-
                 Test-support code belongs in test files and in packages whose
                 directory name ends in test, not in the shipped binary.
+            - pkg: sneak.berlin/go/vaultik/internal/storage/faultstore
+              desc: >-
+                Test-support code belongs in test files and in packages whose
+                directory name ends in test, not in the shipped binary.
     # Only decisions already recorded in the Go package defaults are
     # listed here. Every entry matches the module path exactly.
     gomodguard_v2: