Phase 2/3: Employees list/detail + mutation RPCs + action panels

- supabase/functions.sql, functions_2.sql: Postgres RPCs for every
  employee/position/reorg mutation (hire, terminate, transfer, promote,
  start/adjust/return karenz, change data, rehire, create position, staff
  internally, apply/undo reorg). Each resolves manager_id server-side,
  writes history + audit atomically, and enforces hr_admin via
  require_hr_admin() (backed by the existing RLS policy).
- actions/employees.ts, positions.ts, reorg.ts: Server Actions wrapping
  the RPCs, returning success/error for client-side toast handling.
- Employees list (search/filter/pagination) and detail (4 tabs: Stammdaten,
  Vertrag & Gehalt, Organisation, Historie) reading from employees_directory.
- 6 action slide-over panels: Transfer, Promote, Karenz (start/adjust/
  return), Daten aendern (person+contract diffing), Terminate (with direct-
  report reparenting warning + offboarding checklist), Rehire.
- lib/org.ts: shared division/department/team/location lookups.

Verified live: promote mutation updates salary, writes history/audit, and
the detail page reflects it after refresh, no console errors.

Note: the spec's Karenz-verwalten panel only covers employees already on
Karenz; added a start-Karenz mode (Karenzbeginn/geplante Rueckkehr) to
cover the Aktiv-employee case implied by the header button but not
specified in the panel list.

components/employees/panels/PromotePanel.tsx

@@ -0,0 +1,114 @@
+"use client";
+
+import { useRouter } from "next/navigation";
+import { useState } from "react";
+import { promoteEmployee } from "@/actions/employees";
+import { SlideOver } from "@/components/ui/SlideOver";
+import { useToast } from "@/components/ui/Toast";
+import type { Database, PaygradeType } from "@/lib/supabase/types";
+
+type EmployeeRow = Database["public"]["Views"]["employees_directory"]["Row"];
+
+const PAYGRADES: { value: PaygradeType; label: string }[] = [
+  { value: "A", label: "A – Einstieg" },
+  { value: "B", label: "B – Qualifiziert" },
+  { value: "C", label: "C – Erfahren" },
+  { value: "D", label: "D – Spezialist:in" },
+  { value: "E", label: "E – Teamleitung" },
+  { value: "F", label: "F – Bereichsleitung / GF" },
+];
+
+export function PromotePanel({ open, onClose, employee }: { open: boolean; onClose: () => void; employee: EmployeeRow }) {
+  const { showToast } = useToast();
+  const router = useRouter();
+  const [effectiveDate, setEffectiveDate] = useState("");
+  const [newTitle, setNewTitle] = useState(employee.job_title);
+  const [newSalary, setNewSalary] = useState(String(employee.monthly_salary_gross ?? ""));
+  const [paygrade, setPaygrade] = useState<PaygradeType>(employee.paygrade);
+  const [pending, setPending] = useState(false);
+
+  async function handleSubmit() {
+    if (!effectiveDate || !newTitle || !newSalary) {
+      showToast("Bitte alle Pflichtfelder ausfüllen.", "error");
+      return;
+    }
+    setPending(true);
+    const result = await promoteEmployee({
+      employee_id: employee.id,
+      effective_date: effectiveDate,
+      new_title: newTitle,
+      new_salary: Number(newSalary),
+      new_paygrade: paygrade,
+    });
+    setPending(false);
+    if (result.success) {
+      showToast(`${employee.first_name} ${employee.last_name} wurde befördert.`);
+      router.refresh();
+      onClose();
+    } else {
+      showToast(result.error ?? "Fehler beim Speichern.", "error");
+    }
+  }
+
+  return (
+    <SlideOver
+      open={open}
+      onClose={onClose}
+      title="Beförderung"
+      subtitle={`${employee.first_name} ${employee.last_name} · ${employee.job_title}`}
+      footer={
+        <>
+          <button onClick={onClose} className="rounded px-4 py-2 text-sm font-semibold text-ink-body hover:bg-surface">
+            Abbrechen
+          </button>
+          <button
+            onClick={handleSubmit}
+            disabled={pending}
+            className="rounded bg-purple-text px-4 py-2 text-sm font-semibold text-white disabled:opacity-50"
+          >
+            Befördern
+          </button>
+        </>
+      }
+    >
+      <div className="flex flex-col gap-4">
+        <div>
+          <label className="mb-1 block text-sm font-semibold text-ink">Wirksam ab*</label>
+          <input
+            type="date"
+            value={effectiveDate}
+            onChange={(e) => setEffectiveDate(e.target.value)}
+            className="w-full rounded border border-border px-3 py-2 text-sm"
+          />
+        </div>
+        <div>
+          <label className="mb-1 block text-sm font-semibold text-ink">Neue Position*</label>
+          <input value={newTitle} onChange={(e) => setNewTitle(e.target.value)} className="w-full rounded border border-border px-3 py-2 text-sm" />
+        </div>
+        <div>
+          <label className="mb-1 block text-sm font-semibold text-ink">Neues Bruttogehalt (14x/Jahr)*</label>
+          <input
+            type="number"
+            value={newSalary}
+            onChange={(e) => setNewSalary(e.target.value)}
+            className="w-full rounded border border-border px-3 py-2 text-sm"
+          />
+        </div>
+        <div>
+          <label className="mb-1 block text-sm font-semibold text-ink">Paygrade</label>
+          <select
+            value={paygrade}
+            onChange={(e) => setPaygrade(e.target.value as PaygradeType)}
+            className="w-full rounded border border-border px-3 py-2 text-sm"
+          >
+            {PAYGRADES.map((p) => (
+              <option key={p.value} value={p.value}>
+                {p.label}
+              </option>
+            ))}
+          </select>
+        </div>
+      </div>
+    </SlideOver>
+  );
+}