feat(web): published-versions sidebar on the composer page

The lab redesign gave only the lab tab the published-history sidebar;
the composer page was expected to have it too. /setup/tariff now lists
every published version (name or effective date, active badge, currency)
on the right; clicking one loads it into the editor as the SEED for the
next publish — which always creates a new immutable version (the sidebar
hint states this), making "roll back to last month's prices" a two-click
republish while the history stays append-only.

Claude-Session: https://claude.ai/code/session_01Xcm6ikLgGoCxxHrxtjkk5V

apps/web/src/lib/i18n/en.ts

@@ -336,6 +336,9 @@ export const en: Catalog = {
     publishNewVersion: "Publish new version",
     publishing: "Publishing…",
     versionNamePh: "Version name (optional), e.g. Summer 2026",
+    versionsTitle: "Published versions",
+    versionsHint: "Click one to load it into the editor. Publishing always creates a new version — past versions never change.",
+    activeBadge: "active",
     publishedOk: "New tariff version published — it's now the active rate.",
     defaultCard: "Base rate (always active)",
     defaultCardHint: "The base rate applied when no time/seasonal tier matches. This alone is enough for most car parks.",