fix: close all remaining known gaps across modules

Every 'read-only placeholder' and 'missing functionality' gap from the
QA audit is now resolved:

COURSES — categories/instructors/locations can now be deleted:
- Added update/delete methods to course-reference-data.service.ts
- Added deleteCategory/deleteInstructor/deleteLocation server actions
- Created DeleteRefDataButton client component with confirmation dialog
- Wired delete buttons into all three table pages

BOOKINGS — calendar month navigation now works:
- Calendar was hardcoded to current month with disabled prev/next
- Added year/month search params for server-side month rendering
- Replaced disabled buttons with Link-based navigation
- Verified: clicking next/prev correctly renders different months

DOCUMENTS — templates page now reads from database:
- Was hardcoded empty array; now queries document_templates table
- Table exists since migration 20260414000006_shared_templates.sql

FISCHEREI — statistics page shows real data:
- Replaced dashed-border placeholder with 6 real stat cards
- Queries waters, species, stocking, catch_books, leases, permits
- Shows counts + stocking costs + pending catch books
- Falls back to helpful message when no data exists

VERBAND — statistics page shows real KPIs:
- Added server-side data fetching (clubs, members, fees)
- Passes activeClubs, totalMembers, openFees as props
- Added 4 KPI cards: Aktive Vereine, Gesamtmitglieder,
  ∅ Mitglieder/Verein, Offene Beiträge
- Kept existing trend charts below KPI cards

apps/web/app/[locale]/home/[account]/fischerei/statistics/page.tsx

@@ -24,6 +24,29 @@ export default async function StatisticsPage({ params }: Props) {
 
   if (!acct) return <AccountNotFound />;
 
+  // Fetch actual statistics from existing tables
+  const [watersResult, speciesResult, stockingResult, catchBooksResult, leasesResult, permitsResult] = await Promise.allSettled([
+    client.from('waters').select('id', { count: 'exact' }).eq('account_id', acct.id),
+    client.from('fish_species').select('id', { count: 'exact' }).eq('account_id', acct.id),
+    client.from('fish_stocking').select('id, quantity, cost_total', { count: 'exact' }).eq('account_id', acct.id),
+    client.from('catch_books').select('id, status', { count: 'exact' }).eq('account_id', acct.id),
+    client.from('fishing_leases').select('id', { count: 'exact' }).eq('account_id', acct.id).eq('status', 'active'),
+    client.from('fishing_permits').select('id', { count: 'exact' }).eq('account_id', acct.id),
+  ]);
+
+  const waterCount = watersResult.status === 'fulfilled' ? (watersResult.value.count ?? 0) : 0;
+  const speciesCount = speciesResult.status === 'fulfilled' ? (speciesResult.value.count ?? 0) : 0;
+  const stockingData = stockingResult.status === 'fulfilled' ? (stockingResult.value.data ?? []) : [];
+  const stockingCount = stockingData.length;
+  const stockingCost = stockingData.reduce((sum: number, s: any) => sum + (Number(s.cost_total) || 0), 0);
+  const catchBookCount = catchBooksResult.status === 'fulfilled' ? (catchBooksResult.value.count ?? 0) : 0;
+  const catchBookData = catchBooksResult.status === 'fulfilled' ? (catchBooksResult.value.data ?? []) : [];
+  const pendingCatchBooks = catchBookData.filter((cb: any) => cb.status === 'submitted').length;
+  const leaseCount = leasesResult.status === 'fulfilled' ? (leasesResult.value.count ?? 0) : 0;
+  const permitCount = permitsResult.status === 'fulfilled' ? (permitsResult.value.count ?? 0) : 0;
+
+  const formatCurrency = (v: number) => new Intl.NumberFormat('de-DE', { style: 'currency', currency: 'EUR' }).format(v);
+
   return (
     <CmsPageShell account={account} title={t('pages.statisticsTitle')}>
       <FischereiTabNavigation account={account} activeTab="statistics" />
@@ -33,22 +56,27 @@ export default async function StatisticsPage({ params }: Props) {
             Fangstatistiken und Auswertungen
           </p>
         </div>
+        <div className="grid grid-cols-1 gap-4 sm:grid-cols-2 lg:grid-cols-3">
+          <Card><CardContent className="p-6"><p className="text-muted-foreground text-sm">Gewässer</p><p className="text-2xl font-bold">{waterCount}</p></CardContent></Card>
+          <Card><CardContent className="p-6"><p className="text-muted-foreground text-sm">Fischarten</p><p className="text-2xl font-bold">{speciesCount}</p></CardContent></Card>
+          <Card><CardContent className="p-6"><p className="text-muted-foreground text-sm">Besatzaktionen</p><p className="text-2xl font-bold">{stockingCount}</p><p className="text-muted-foreground text-xs">{formatCurrency(stockingCost)} Gesamtkosten</p></CardContent></Card>
+          <Card><CardContent className="p-6"><p className="text-muted-foreground text-sm">Fangbücher</p><p className="text-2xl font-bold">{catchBookCount}</p>{pendingCatchBooks > 0 && <p className="text-xs text-amber-600">{pendingCatchBooks} zur Prüfung</p>}</CardContent></Card>
+          <Card><CardContent className="p-6"><p className="text-muted-foreground text-sm">Aktive Pachten</p><p className="text-2xl font-bold">{leaseCount}</p></CardContent></Card>
+          <Card><CardContent className="p-6"><p className="text-muted-foreground text-sm">Erlaubnisscheine</p><p className="text-2xl font-bold">{permitCount}</p></CardContent></Card>
+        </div>
+
+        {waterCount === 0 && speciesCount === 0 && (
         <Card>
-          <CardHeader>
-            <CardTitle>Fangstatistiken</CardTitle>
-          </CardHeader>
-          <CardContent>
-            <div className="flex flex-col items-center justify-center rounded-lg border border-dashed p-12 text-center">
-              <h3 className="text-lg font-semibold">
-                Noch keine Daten vorhanden
-              </h3>
+          <CardContent className="p-6">
+            <div className="flex flex-col items-center justify-center rounded-lg border border-dashed p-8 text-center">
+              <h3 className="text-lg font-semibold">Noch keine Daten vorhanden</h3>
               <p className="text-muted-foreground mt-1 max-w-sm text-sm">
-                Sobald Fangbücher eingereicht und geprüft werden, erscheinen
-                hier Statistiken und Auswertungen.
+                Sobald Gewässer, Fischarten und Fangbücher angelegt werden, erscheinen hier detaillierte Statistiken.
               </p>
             </div>
           </CardContent>
         </Card>
+        )}
       </div>
     </CmsPageShell>
   );