feat(04-03): project workspace + timer analytics + settings page

- /admin/projects/[id]: full workspace with 7 tabs (Fasi, Pagamenti,
  Documenti, Note, Commenti, Preventivo, Timer)
- TimerTab: TimerCell + ProfitabilityCard with €/h real, ideal cost, delta
- ProfitabilityCard: hours worked, €/h real vs target, profit/loss delta
- /admin/impostazioni: target_hourly_rate setting (default 50€/h)
- actions.ts: resolveEntity() helper — actions now work transparently
  with both clientId and projectId (same tab components reused)
- quote-actions.ts: same resolveEntity pattern for addQuoteItem,
  removeQuoteItem, updateAcceptedTotal
- timer-actions.ts: revalidate /admin/projects and /admin/projects/[id]

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/components/admin/tabs/TimerTab.tsx

@@ -0,0 +1,42 @@
+"use client";
+
+import { TimerCell } from "@/components/admin/TimerCell";
+import { ProfitabilityCard } from "@/components/admin/ProfitabilityCard";
+
+type TimerTabProps = {
+  projectId: string;
+  acceptedTotal: string;
+  activeTimerEntryId: string | null;
+  activeTimerStartedAt: Date | null;
+  totalTrackedSeconds: number;
+  targetHourlyRate: number;
+};
+
+export function TimerTab({
+  projectId,
+  acceptedTotal,
+  activeTimerEntryId,
+  activeTimerStartedAt,
+  totalTrackedSeconds,
+  targetHourlyRate,
+}: TimerTabProps) {
+  return (
+    <div className="space-y-6 max-w-sm">
+      <div className="bg-white rounded-lg border border-[#e5e7eb] p-4">
+        <h3 className="font-medium text-[#1a1a1a] mb-4">Timer</h3>
+        <TimerCell
+          clientId={projectId}
+          activeEntryId={activeTimerEntryId}
+          activeStartedAt={activeTimerStartedAt}
+          totalTrackedSeconds={totalTrackedSeconds}
+        />
+      </div>
+
+      <ProfitabilityCard
+        acceptedTotal={acceptedTotal}
+        totalTrackedSeconds={totalTrackedSeconds}
+        targetHourlyRate={targetHourlyRate}
+      />
+    </div>
+  );
+}