chore: add i18n dict consistency lint rule

web/eslint-plugins/i18n/index.js

@@ -0,0 +1,20 @@
+/**
+ * Local ESLint plugin "i18n".
+ *
+ * Cross-locale dictionary hygiene (i18n/dict-consistency): every locale dict in
+ * `lib/i18n/` is compared against all the others — key parity, empty values,
+ * `{placeholder}` parity — warn-only by design (a missing translation must not
+ * break the build). The set of locales comes from `LOCALES` in `dict.ts`, so
+ * new locales are picked up automatically.
+ */
+import dictConsistency from "./dict-consistency.js";
+
+export default {
+	meta: {
+		name: "i18n",
+		version: "0.1.0",
+	},
+	rules: {
+		"dict-consistency": dictConsistency,
+	},
+};