fix(dates): show the year whenever a date is not the current one

Sweeps every surface that renders a date from before this year without
a year suffix — illness episodes/flares/day-logs, lab and custom-metric
charts, the mood chart family, medication titration/side-effects/dose-
history/next-dose captions (incl. the Dec→Jan rollover), cycle
predictions and history, the BBT chart, the intraday-pulse day-nav, the
date-range filter chip, and the nutrient/compliance charts. Each now
routes through dateShortSmart / dateWithWeekdaySmart (format-locale.ts)
or the matching date-format.ts helper, which add the year only when it
differs from the current one — mirroring the workout list's existing
model instead of a bare "19.02." that reads as this year's.

Also fixes two sites that bypassed the app's locale entirely: the
trusted-devices expiry (bare toLocaleDateString, host locale) and the
admin token-name timestamp (hard-coded de-DE + Europe/Berlin) now both
render through the user's own locale, hour-cycle, and timezone
preference.

src/components/cycle/bbt-chart.tsx

@@ -191,7 +191,9 @@ export function BbtChart({
                     scale="time"
                     domain={["dataMin", "dataMax"]}
                     ticks={ticks}
-                    tickFormatter={(v) => fmt.dateShort(new Date(v as number))}
+                    tickFormatter={(v) =>
+                      fmt.dateShortSmart(new Date(v as number))
+                    }
                     tick={{ fontSize: 11, fill: "var(--muted-foreground)" }}
                     tickLine={false}
                     axisLine={false}
@@ -285,7 +287,9 @@ function BbtTooltip(props: {
         "bg-popover border-border rounded-md border px-2.5 py-2 text-xs shadow-md",
       )}
     >
-      <p className="text-muted-foreground">{fmt.dateShort(new Date(p.t))}</p>
+      <p className="text-muted-foreground">
+        {fmt.dateShortSmart(new Date(p.t))}
+      </p>
       <p className="text-foreground font-medium tabular-nums">
         {t("cycle.bbt.tooltipTemp", { temp: fmt.number(p.temp) })}
       </p>

src/components/cycle/predictions-panel.tsx

@@ -11,7 +11,8 @@ import {
 } from "@/components/ui/card";
 import { Badge } from "@/components/ui/badge";
 import { TileHeader } from "@/components/insights/tile-header";
-import { useTranslations } from "@/lib/i18n/context";
+import { useTranslations, useFormatters } from "@/lib/i18n/context";
+import type { Formatters } from "@/lib/format-locale";
 import { FERTILE_HUE, FLOW_HUE, OVULATION_HUE } from "./phase-tokens";
 import type { CyclePrediction, CycleHistoryResponse } from "./types";
 
@@ -26,12 +27,17 @@ import type { CyclePrediction, CycleHistoryResponse } from "./types";
  * cycle-tracking on-ramp, not repeated beneath every prediction surface.
  */
 
-function formatDate(d: string): string {
+/**
+ * Issue #66 — was a bespoke `toLocaleDateString(undefined, …)` (browser
+ * locale, never the app's) with no year. Predictions run 1-2 cycles out, so
+ * a window straddling New Year's would otherwise print an unadorned "Jan 3"
+ * in December. Routes through the app-locale conditional-year formatter
+ * instead; `dateShortSmart` already renders day+month in the locale's field
+ * order and only adds the year when it differs from the current one.
+ */
+function formatDate(d: string, fmt: Formatters): string {
   // Render at noon UTC so the YYYY-MM-DD never rolls a day across tz.
-  return new Date(`${d}T12:00:00Z`).toLocaleDateString(undefined, {
-    month: "short",
-    day: "numeric",
-  });
+  return fmt.dateShortSmart(`${d}T12:00:00Z`);
 }
 
 function confidenceTone(c: number): {
@@ -60,6 +66,7 @@ export function PredictionsPanel({
   history,
 }: PredictionsPanelProps) {
   const { t } = useTranslations();
+  const fmt = useFormatters();
 
   return (
     <div className="space-y-4">
@@ -92,8 +99,9 @@ export function PredictionsPanel({
                 <Row
                   hue={FERTILE_HUE}
                   label={t("cycle.predictions.fertileWindow")}
-                  value={`${formatDate(prediction.fertileWindowStart)} – ${formatDate(
+                  value={`${formatDate(prediction.fertileWindowStart, fmt)} – ${formatDate(
                     prediction.fertileWindowEnd,
+                    fmt,
                   )}`}
                 />
               ) : null}
@@ -105,7 +113,7 @@ export function PredictionsPanel({
                       ? t("cycle.predictions.ovulationConfirmed")
                       : t("cycle.predictions.ovulation")
                   }
-                  value={formatDate(prediction.predictedOvulation)}
+                  value={formatDate(prediction.predictedOvulation, fmt)}
                 />
               ) : null}
             </>
@@ -120,6 +128,7 @@ export function PredictionsPanel({
 
 function NextPeriod({ prediction }: { prediction: CyclePrediction }) {
   const { t } = useTranslations();
+  const fmt = useFormatters();
   const tone = confidenceTone(prediction.confidence);
   return (
     <div className="space-y-1.5">
@@ -128,8 +137,8 @@ function NextPeriod({ prediction }: { prediction: CyclePrediction }) {
           hue={FLOW_HUE}
           label={t("cycle.predictions.nextPeriod")}
           value={t("cycle.predictions.nextPeriodWindow", {
-            low: formatDate(prediction.nextPeriodStartLow),
-            high: formatDate(prediction.nextPeriodStartHigh),
+            low: formatDate(prediction.nextPeriodStartLow, fmt),
+            high: formatDate(prediction.nextPeriodStartHigh, fmt),
           })}
         />
         <Badge variant={tone.variant} className="shrink-0">
@@ -186,6 +195,7 @@ function HistoryCard({
   history: CycleHistoryResponse | undefined;
 }) {
   const { t } = useTranslations();
+  const fmt = useFormatters();
   const stats = history?.stats;
   // Most-recent observed cycles (the spread the regularity number summarises —
   // seeing it builds trust; the data was already on the wire). QA H2.
@@ -253,10 +263,10 @@ function HistoryCard({
                     className="flex items-center justify-between gap-3 py-2 text-sm"
                   >
                     <span className="text-foreground tabular-nums">
-                      {formatDate(c.startDate)}
+                      {formatDate(c.startDate, fmt)}
                       {" – "}
                       {c.endDate
-                        ? formatDate(c.endDate)
+                        ? formatDate(c.endDate, fmt)
                         : t("cycle.history.ongoing")}
                     </span>
                     <span className="text-muted-foreground flex items-center gap-2 tabular-nums">