fix(items): auto-sort by distance when site selected or changed

useEffect keyed on currentSiteId resets sortBy to 'distance' whenever
the site selection changes, overcoming useState's one-time initialisation
which didn't fire on soft navigations (state preserved across router.push).

Verified with Playwright: no-site→price, select-site→distance auto,
manual price switch works, switch-site→distance resets.

App/pelagia-portal/app/(portal)/inventory/items/items-table.tsx

@@ -1,6 +1,6 @@
 "use client";
 
-import { useState, useMemo, Fragment } from "react";
+import { useState, useMemo, Fragment, useEffect } from "react";
 import { useRouter } from "next/navigation";
 import Link from "next/link";
 import { Search, X, ChevronDown, ChevronRight, MapPin, Tag } from "lucide-react";
@@ -46,6 +46,11 @@ export function ItemsTable({
   const [sortBy, setSortBy] = useState<"distance" | "price">(hasSite ? "distance" : "price");
   const [added, setAdded] = useState<Record<string, boolean>>({});
 
+  // Reset sort to distance whenever the selected site changes
+  useEffect(() => {
+    setSortBy(currentSiteId ? "distance" : "price");
+  }, [currentSiteId]);
+
   const filtered = useMemo(() => {
     const q = query.toLowerCase().trim();
     if (!q) return items;