feat(shift): two-pane shift history — list + per-shift activity log, timeframe presets

Rework the shift screen into a master/detail view on /shift: the shift CONTROL
(open/close, drawer vouchers, X-report) on top, then a two-pane history below —
shift list on the LEFT, the selected shift's signed activity log on the RIGHT.

- Timeframe presets replace the bare from/to inputs: Yesterday / Last week /
  Last month / All / Custom (custom reveals the date pickers). Filters the shift
  list by start time.
- Activity log = every ledger event in the selected shift's [start, end] window
  (entries, exits, payments, vouchers, anomalies, the Z-report), rendered like the
  booth live feed (same EVENT_STYLE), with the shift's drawer reconciliation in the
  pane header.
- Scope unchanged + enforced SERVER-SIDE: an operator sees only their own shifts
  (no operator filter); an admin (shift:cash) sees all + the operator filter. The
  list auto-selects the newest shift.

API: /api/events gains an optional `until` (ISO) upper bound so a shift's window
can be fetched ([start,end]); fetchEvents passes it. Verified on live data: a
closed shift window returns just its 20 events out of 260.

Build+lint 12/12 (i18n parity). The same component also backs /setup/shifts.

Claude-Session: https://claude.ai/code/session_01Xcm6ikLgGoCxxHrxtjkk5V

apps/web/src/lib/i18n/sq.ts

@@ -645,6 +645,14 @@ export const sq = {
     allOperators: "Të gjithë operatorët",
     apply: "Apliko",
     clear: "Pastro",
+    timeframe: "Periudha",
+    preset_yesterday: "Dje",
+    preset_week: "Javën e fundit",
+    preset_month: "Muajin e fundit",
+    preset_all: "Të gjitha",
+    preset_custom: "E zgjedhur",
+    selectAShift: "Zgjidh një turn për të parë aktivitetin e tij.",
+    noActivity: "Asnjë aktivitet në këtë turn.",
     // Expanded drawer detail.
     drawerSection: "Arka",
     openingFloat: "Bilanci fillestar",