Org assignment history, mobile support, and a correctness pass

Data model
- employee_assignments records org placement over time (valid_from/valid_to),
  written by a trigger on `employees` rather than inside each RPC: ~70
  `update employees` statements spread over fifteen migrations mean per-call
  bookkeeping would miss paths today and again with every future RPC. A
  partial unique index enforces the one-open-interval invariant the trigger
  relies on when closing the current row.
- The Organigramm gains a Stichtag (default today). Membership comes from
  entry/exit/karenz, past placement from the new history, future placement
  projected from pending_org_changes. Placements predating the migration are
  backfilled with today's values and flagged as such in the UI, since
  employee_history only ever stored free text and cannot be reconstructed.

Correctness
- Reports and exports silently truncated at PostgREST's 1000-row cap
  (db.max_rows); employee_history is already past it at ~800 staff. Every
  whole-table read now pages explicitly.
- XLSX date cells were a day early: ExcelJS converts a Date to an Excel
  serial straight off getTime(), so a Date built at local midnight lands on
  the previous day's serial in any positive-offset zone.
- Date handling is pinned to Europe/Vienna throughout, and date-only strings
  are formatted without a Date round-trip. The dashboard's YTD window was
  built by round-tripping a local Date through toISOString(), which shifted
  it a day early and dropped 31 December entirely.
- Export routes parsed measure/group/split/eventType with unchecked `as`
  casts, so an unknown value reached column headers as `undefined` and the
  Content-Disposition filename. Parsed against the label maps now, with the
  filename slugged as a backstop.
- toXlsx keyed columns by header text, silently dropping the second of any
  two columns sharing a name — split columns take their header from data.
- The org chart tree walks had no cycle guard; nothing in the schema forbids
  a manager_id cycle, and one would hang the tab rather than misreport.
- The login page reflected ?error= verbatim, letting anyone put arbitrary
  text on the real sign-in screen; messages are looked up by code now.
- React Flow needs elementsSelectable on, or it sets pointer-events:none on
  the whole node and the expand control stops responding.

UI
- Mobile: the shell was unusable below lg — a fixed 236px margin pushed
  content off-screen with no mobile navigation at all. The sidebar is now a
  drawer, dvh replaces vh, safe-area insets are honoured, inputs are 16px so
  iOS stops zooming on focus, and form grids stack.
- Org chart nodes redesigned: per-kind accent stripes and icons, vacant
  roles called out, expand control moved to the bottom edge carrying the
  child count.
- Pagination is windowed; it previously rendered one link per page (54 for
  the employee list, unbounded for the audit log).
- Positions page reduced to open positions with a single "Besetzen" action.
- The employee Organisation tab links into the org chart focused on that
  person, reusing the chart's existing search-match highlighting.

Also included, uncommitted until now
- Dependants, HR notes, academic titles, split address fields, position
  validity and role/employment fields, with their migrations and UI.
- Docker/compose deployment setup, data-model and security-review docs.

components/employees/AngehoerigeSection.tsx

@@ -0,0 +1,96 @@
+"use client";
+
+import { Plus, Trash2 } from "lucide-react";
+import { useRouter } from "next/navigation";
+import { useState } from "react";
+import { deleteEmployeeDependent } from "@/actions/employees";
+import { useToast } from "@/components/ui/Toast";
+import { fmtDate, todayIso } from "@/lib/format";
+import type { Database } from "@/lib/supabase/types";
+import { AddDependentModal } from "./AddDependentModal";
+
+type Dependent = Database["public"]["Tables"]["employee_dependents"]["Row"];
+
+// `effectiveDate` lets DatenAendernPanel embed this section and drive
+// add/remove off its own "Wirksam ab" field; standalone usage (Stammdaten
+// tab) omits it and defaults to today, i.e. immediate.
+export function AngehoerigeSection({ employeeId, dependents, effectiveDate }: { employeeId: string; dependents: Dependent[]; effectiveDate?: string }) {
+  const { showToast } = useToast();
+  const router = useRouter();
+  const [modalOpen, setModalOpen] = useState(false);
+  const [deletingId, setDeletingId] = useState<string | null>(null);
+  const resolvedEffectiveDate = effectiveDate || todayIso();
+
+  async function handleDelete(dependentId: string) {
+    setDeletingId(dependentId);
+    const result = await deleteEmployeeDependent({ dependent_id: dependentId, employee_id: employeeId, effective_date: resolvedEffectiveDate });
+    setDeletingId(null);
+    if (result.success) {
+      showToast("Angehörige:r entfernt.");
+      router.refresh();
+    } else {
+      showToast(result.error ?? "Fehler beim Entfernen.", "error");
+    }
+  }
+
+  return (
+    <div className="border-t border-border pt-6">
+      <div className="mb-3 flex items-center justify-between">
+        <h3 className="text-xs font-bold uppercase tracking-wide text-brand-700">Angehörige</h3>
+        <div className="flex items-center gap-4">
+          <button
+            type="button"
+            onClick={() => setModalOpen(true)}
+            className="flex items-center gap-1 text-xs font-semibold text-brand-700 hover:text-brand-600"
+          >
+            <Plus className="h-3.5 w-3.5" /> Hinzufügen
+          </button>
+          <span className="text-xs text-ink-muted">{dependents.length} Personen</span>
+        </div>
+      </div>
+
+      {dependents.length === 0 ? (
+        <p className="text-sm text-ink-muted">Keine Angehörigen hinterlegt.</p>
+      ) : (
+        <div className="overflow-x-auto rounded border border-border">
+          <table className="w-full min-w-[600px] text-sm">
+            <thead>
+              <tr className="border-b border-border bg-brand-50 text-left text-xs font-semibold uppercase tracking-wide text-ink-muted">
+                <th className="px-4 py-2.5">Name</th>
+                <th className="px-4 py-2.5">Verhältnis</th>
+                <th className="px-4 py-2.5">SVNR</th>
+                <th className="px-4 py-2.5">Geburtsdatum</th>
+                <th className="px-4 py-2.5" />
+              </tr>
+            </thead>
+            <tbody>
+              {dependents.map((d) => (
+                <tr key={d.id} className="border-b border-border last:border-0">
+                  <td className="px-4 py-2.5 font-semibold text-ink">
+                    {d.first_name} {d.last_name}
+                  </td>
+                  <td className="px-4 py-2.5 text-ink-body">{d.relationship}</td>
+                  <td className="px-4 py-2.5 text-ink-body">{d.sv_nummer ?? "–"}</td>
+                  <td className="px-4 py-2.5 text-ink-body">{fmtDate(d.birth_date)}</td>
+                  <td className="px-4 py-2.5 text-right">
+                    <button
+                      type="button"
+                      onClick={() => handleDelete(d.id)}
+                      disabled={deletingId === d.id}
+                      aria-label="Angehörige:n entfernen"
+                      className="text-ink-muted hover:text-danger-solid disabled:opacity-50"
+                    >
+                      <Trash2 className="h-3.5 w-3.5" />
+                    </button>
+                  </td>
+                </tr>
+              ))}
+            </tbody>
+          </table>
+        </div>
+      )}
+
+      <AddDependentModal open={modalOpen} onClose={() => setModalOpen(false)} employeeId={employeeId} defaultEffectiveDate={resolvedEffectiveDate} />
+    </div>
+  );
+}