feat(dashboard): real data — metrics, charts, top customers, recent transactions

Dashboard is no longer mock data. Single getDashboardData(tenantId) server
query computes everything in one pass.

New aggregator (lib/appwrite/dashboard-queries.ts):
- Pulls customers, invoices, finance_entries, tasks, services in parallel.
- Derives:
  * metrics: totalCustomers, activeCustomers, monthIncome,
    prevMonthIncome (for delta), outstanding (unpaid invoice total),
    overdueCount, openTasks, urgentTasks
  * monthlyIncome: 12-month income+expense series for area chart
  * topCustomers: 5 highest-grossing customers by paid invoice total
  * recentTransactions: 8 newest finance entries
  * topServices: 5 services by aggregate unit price (placeholder, will
    refine when we have invoice line analytics)
  * newCustomersMonthly: 6-month new customer count for bar chart

Components (dashboard/components/):
- Metrics: 4 cards with trend indicator on income (delta vs previous
  month), warning tone on overdue invoices and urgent tasks.
- IncomeChart: Recharts Area chart, dual income/expense series with
  gradient fills, Turkish month labels.
- TopCustomers: ranked list with progress bars relative to top earner.
- RecentTransactions: list with type badge, signed amount, link to
  /finance for full list.
- CustomerGrowth: BarChart of new customers per month (last 6).
- QuickActions: 4 buttons linking to /customers, /invoices, /calendar,
  /tasks (replaced template's New User/Add Product/etc).

Layout: 4 metric cards row, then income chart + top customers (2-col),
then recent transactions + customer growth (2-col).

Removed:
- src/app/(dashboard)/dashboard-2/ (was the demo page; same components
  re-exported into the real /dashboard from there. Now /dashboard owns
  its components.)
- 'Dashboard 2' entry from CommandSearch; replaced with our actual
  module list (Müşteriler / Hizmetler / Yazılımlarımız / Takvim /
  Görevler / Gelir-Gider / Faturalar).

src/app/(dashboard)/dashboard/components/metrics.tsx

@@ -0,0 +1,112 @@
+import {
+  AlertCircle,
+  ArrowDownRight,
+  ArrowUpRight,
+  CheckSquare,
+  Receipt,
+  Users,
+  Wallet,
+} from "lucide-react";
+
+import { Card, CardContent } from "@/components/ui/card";
+import { formatTRY } from "@/lib/format";
+import { cn } from "@/lib/utils";
+
+import type { DashboardData } from "@/lib/appwrite/dashboard-queries";
+
+function delta(current: number, previous: number): { pct: number; positive: boolean } | null {
+  if (previous === 0) {
+    if (current === 0) return null;
+    return { pct: 100, positive: true };
+  }
+  const pct = ((current - previous) / previous) * 100;
+  return { pct: Math.abs(pct), positive: pct >= 0 };
+}
+
+export function Metrics({ data }: { data: DashboardData["metrics"] }) {
+  const incomeDelta = delta(data.monthIncome, data.prevMonthIncome);
+
+  const cards = [
+    {
+      label: "Müşteriler",
+      value: String(data.totalCustomers),
+      sub: `${data.activeCustomers} aktif`,
+      icon: Users,
+      tone: "default",
+    },
+    {
+      label: "Bu ayki gelir",
+      value: formatTRY(data.monthIncome),
+      sub: incomeDelta
+        ? `${incomeDelta.positive ? "+" : "−"}${incomeDelta.pct.toFixed(1)}% önceki ay`
+        : "Geçen ay veri yok",
+      icon: Wallet,
+      tone: "income",
+      trend: incomeDelta,
+    },
+    {
+      label: "Bekleyen tahsilat",
+      value: formatTRY(data.outstanding),
+      sub:
+        data.overdueCount > 0
+          ? `${data.overdueCount} vadesi geçmiş`
+          : "Vadesi geçmiş yok",
+      icon: Receipt,
+      tone: data.overdueCount > 0 ? "warning" : "default",
+    },
+    {
+      label: "Açık görevler",
+      value: String(data.openTasks),
+      sub:
+        data.urgentTasks > 0 ? `${data.urgentTasks} acil` : "Acil görev yok",
+      icon: CheckSquare,
+      tone: data.urgentTasks > 0 ? "warning" : "default",
+    },
+  ];
+
+  const toneClass: Record<string, string> = {
+    default: "text-muted-foreground",
+    income: "text-emerald-600 dark:text-emerald-400",
+    warning: "text-amber-600 dark:text-amber-400",
+  };
+
+  return (
+    <div className="grid gap-4 sm:grid-cols-2 @5xl:grid-cols-4">
+      {cards.map((c) => {
+        const Icon = c.icon;
+        return (
+          <Card key={c.label}>
+            <CardContent className="flex items-start justify-between p-5">
+              <div>
+                <p className="text-muted-foreground text-xs uppercase tracking-wide">
+                  {c.label}
+                </p>
+                <p className="mt-2 text-2xl font-semibold tabular-nums">{c.value}</p>
+                <p
+                  className={cn(
+                    "mt-1 flex items-center gap-1 text-xs",
+                    c.tone === "warning" && data.overdueCount + data.urgentTasks > 0
+                      ? "text-amber-600 dark:text-amber-400"
+                      : "text-muted-foreground",
+                  )}
+                >
+                  {c.trend &&
+                    (c.trend.positive ? (
+                      <ArrowUpRight className="text-emerald-600 dark:text-emerald-400 size-3" />
+                    ) : (
+                      <ArrowDownRight className="text-red-600 dark:text-red-400 size-3" />
+                    ))}
+                  {c.tone === "warning" && data.overdueCount + data.urgentTasks > 0 && (
+                    <AlertCircle className="size-3" />
+                  )}
+                  {c.sub}
+                </p>
+              </div>
+              <Icon className={cn("size-5", toneClass[c.tone])} />
+            </CardContent>
+          </Card>
+        );
+      })}
+    </div>
+  );
+}