feat(ernten): show only the remaining jars per batch

The batch list on a harvest page no longer states the batch's total
size ("12 von 300 Gläsern verfügbar"). It now reads "Es sind noch 12
Gläser verfügbar", with dedicated wording for a single jar and for a
sold-out batch, which reads scarcer and nudges customers to buy.

Co-Authored-By: Claude Opus 5.5 (1M context) <[email protected]>

src/i18n/dictionaries/en.ts

@@ -761,7 +761,12 @@ export const en: Dictionary = {
     backLabel: "Back to all harvests",
     batchesHeading: "Batches from this harvest",
     productsHeading: "Products from this harvest",
-    glassesAvailable: (remaining, total) => `${remaining} of ${total} jars available`,
+    glassesAvailable: (remaining) =>
+      remaining <= 0
+        ? "Already sold out"
+        : remaining === 1
+          ? "Only 1 jar left"
+          : `Only ${remaining} jars left`,
   },
   chargePage: {
     verifiedBatch: "Verified batch",