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.

tests/unit/reports.test.ts

@@ -4,6 +4,7 @@ import {
   aggregateReport,
   deriveStatusAsOf,
   groupKeyFor,
+  groupKeysFor,
   measureValue,
   MEASURE_LABELS,
   type OrgLookups,
@@ -30,6 +31,14 @@ function emp(overrides: Partial<ReportEmployee> = {}): ReportEmployee {
     paygrade: "B",
     birth_date: "1990-01-01",
     gender: "w",
+    worker_type: "Angestellte:r",
+    collective_agreement: "Handel",
+    work_days: ["Mo", "Di", "Mi", "Do", "Fr"],
+    is_betriebsrat: false,
+    has_dienstwagen: false,
+    is_laterale_fuehrung: false,
+    is_c_level: false,
+    dependents_count: 0,
     ...overrides,
   };
 }
@@ -71,6 +80,35 @@ describe("groupKeyFor", () => {
   it("derives entry_year from entry_date", () => {
     expect(groupKeyFor(emp({ entry_date: "2019-06-01" }), "entry_year", lookups)).toBe("2019");
   });
+
+  it("resolves the Rolle & Anstellung boolean dimensions as Ja/Nein", () => {
+    const e = emp({ is_betriebsrat: true, has_dienstwagen: false, is_laterale_fuehrung: true, is_c_level: false });
+    expect(groupKeyFor(e, "betriebsrat", lookups)).toBe("Ja");
+    expect(groupKeyFor(e, "dienstwagen", lookups)).toBe("Nein");
+    expect(groupKeyFor(e, "laterale_fuehrung", lookups)).toBe("Ja");
+    expect(groupKeyFor(e, "c_level", lookups)).toBe("Nein");
+  });
+
+  it("resolves worker_type/collective_agreement directly", () => {
+    const e = emp({ worker_type: "Arbeiter:in", collective_agreement: "Süßwaren" });
+    expect(groupKeyFor(e, "worker_type", lookups)).toBe("Arbeiter:in");
+    expect(groupKeyFor(e, "collective_agreement", lookups)).toBe("Süßwaren");
+  });
+
+  it("resolves has_dependents from dependents_count", () => {
+    expect(groupKeyFor(emp({ dependents_count: 0 }), "has_dependents", lookups)).toBe("Nein");
+    expect(groupKeyFor(emp({ dependents_count: 2 }), "has_dependents", lookups)).toBe("Ja");
+  });
+});
+
+describe("groupKeysFor", () => {
+  it("returns a single-element array for every ordinary dimension", () => {
+    expect(groupKeysFor(emp(), "division", lookups)).toEqual(["Produktion"]);
+  });
+
+  it("returns one key per work day for the weekday dimension", () => {
+    expect(groupKeysFor(emp({ work_days: ["Mo", "Mi"] }), "weekday", lookups)).toEqual(["Mo", "Mi"]);
+  });
 });
 
 describe("measureValue", () => {
@@ -118,6 +156,11 @@ describe("measureValue", () => {
     ];
     expect(measureValue(rows, "avg_tenure")).toBeCloseTo(3, 0);
   });
+
+  it("computes avg_dependents as the mean dependents_count", () => {
+    const rows = [emp({ dependents_count: 0 }), emp({ dependents_count: 2 }), emp({ dependents_count: 4 })];
+    expect(measureValue(rows, "avg_dependents")).toBeCloseTo(2, 5);
+  });
 });
 
 describe("aggregateReport", () => {
@@ -173,6 +216,23 @@ describe("aggregateReport", () => {
     expect(measureValue(employees, "avg_age", asOf)).toBe(30);
     expect(measureValue(employees, "avg_tenure", asOf)).toBeCloseTo(1.42, 1);
   });
+
+  it("counts an employee once per work day for the weekday dimension, and sorts Mo→So instead of by value", () => {
+    const employees = [
+      emp({ id: "1", work_days: ["Mo", "Di", "Mi", "Do", "Fr"] }),
+      emp({ id: "2", work_days: ["Mo", "Mi", "Fr"] }),
+    ];
+    const rows = aggregateReport(employees, "headcount", "weekday", null, lookups);
+    expect(rows.map((r) => r.key)).toEqual(["Mo", "Di", "Mi", "Do", "Fr"]);
+    expect(rows.find((r) => r.key === "Mo")).toMatchObject({ value: 2, count: 2 });
+    expect(rows.find((r) => r.key === "Di")).toMatchObject({ value: 1, count: 1 });
+  });
+
+  it("sorts a weekday split chronologically within each group", () => {
+    const employees = [emp({ id: "1", division_id: "div-1", work_days: ["Fr", "Mo"] })];
+    const rows = aggregateReport(employees, "headcount", "division", "weekday", lookups);
+    expect(rows[0].split?.map((s) => s.key)).toEqual(["Mo", "Fr"]);
+  });
 });
 
 describe("deriveStatusAsOf", () => {