fix: resolve 6 Gitea issues (#9, #10, #12, #14, #15, #21)

- #21: Add missing await in removeChoiceIfPresent() to prevent user appearing in two restaurants
- #15: Add 1-hour TTL for menu refetching to avoid scraping on every page load
- #9: Block stats API and UI navigation for future dates
- #14: Add restaurant warnings (missing soup/prices, stale data) with warning icon
- #12: Pre-fill restaurant/departure dropdowns from existing choices on page refresh
- #10: Add voting statistics endpoint and table on stats page

types/paths/voting/getVotingStats.yml

@@ -0,0 +1,9 @@
+get:
+  operationId: getVotingStats
+  summary: Vrátí agregované statistiky hlasování o nových funkcích.
+  responses:
+    "200":
+      content:
+        application/json:
+          schema:
+            $ref: "../../schemas/_index.yml#/VotingStats"