feat(i18n): land locale-native date format ordering for FR/ES/IT/PL

Adds a new `format` namespace across every locale bundle that
documents the locale's native date / time pattern ordering as
template strings (`{day}.{month}.{year}`, `{month}/{day}/{year}`, …).
DE keeps DD.MM.YYYY with dot separators, EN keeps MM/DD/YYYY with
slashes, FR/ES/IT adopt DD/MM/YYYY with slashes (the previous
EN-shaped fallback was visibly wrong on French weekly-report PDFs),
PL adopts DD.MM.YYYY with dots.

The runtime `makeFormatters()` helper still routes through `Intl.*`;
the keys exist so PDF / CSV / email surfaces that render outside a
React context can still pick the right ordering hint.

A new smoke test at
`src/lib/i18n/__tests__/format-locale-order.test.ts` pins the
ordering per locale so a copy-paste regression can't silently flip
DD/MM to MM/DD on a non-English bundle.

messages/de.json

@@ -33,6 +33,11 @@
     "showPassword": "Passwort anzeigen",
     "hidePassword": "Passwort verbergen"
   },
+  "format": {
+    "dateShort": "{day}.{month}.{year}",
+    "timeShort": "{hour}:{minute}",
+    "dateTime": "{day}.{month}.{year} {hour}:{minute}"
+  },
   "doctorReport": {
     "title": "Gesundheitsbericht",
     "subtitle": "HealthLog — Persönlicher Gesundheitsbericht",

messages/en.json

@@ -33,6 +33,11 @@
     "showPassword": "Show password",
     "hidePassword": "Hide password"
   },
+  "format": {
+    "dateShort": "{month}/{day}/{year}",
+    "timeShort": "{hour}:{minute}",
+    "dateTime": "{month}/{day}/{year} {hour}:{minute}"
+  },
   "doctorReport": {
     "title": "Health Report",
     "subtitle": "HealthLog — Personal Health Report",

messages/es.json

@@ -33,6 +33,11 @@
     "showPassword": "Mostrar contraseña",
     "hidePassword": "Ocultar contraseña"
   },
+  "format": {
+    "dateShort": "{day}/{month}/{year}",
+    "timeShort": "{hour}:{minute}",
+    "dateTime": "{day}/{month}/{year} {hour}:{minute}"
+  },
   "doctorReport": {
     "title": "Informe de salud",
     "subtitle": "HealthLog — Informe personal de salud",

messages/fr.json

@@ -33,6 +33,11 @@
     "showPassword": "Afficher le mot de passe",
     "hidePassword": "Masquer le mot de passe"
   },
+  "format": {
+    "dateShort": "{day}/{month}/{year}",
+    "timeShort": "{hour}:{minute}",
+    "dateTime": "{day}/{month}/{year} {hour}:{minute}"
+  },
   "doctorReport": {
     "title": "Rapport de santé",
     "subtitle": "HealthLog — Rapport personnel de santé",

messages/it.json

@@ -33,6 +33,11 @@
     "showPassword": "Mostra password",
     "hidePassword": "Nascondi password"
   },
+  "format": {
+    "dateShort": "{day}/{month}/{year}",
+    "timeShort": "{hour}:{minute}",
+    "dateTime": "{day}/{month}/{year} {hour}:{minute}"
+  },
   "doctorReport": {
     "title": "Rapporto sanitario",
     "subtitle": "HealthLog — Rapporto personale di salute",

messages/pl.json

@@ -33,6 +33,11 @@
     "showPassword": "Pokaż hasło",
     "hidePassword": "Ukryj hasło"
   },
+  "format": {
+    "dateShort": "{day}.{month}.{year}",
+    "timeShort": "{hour}:{minute}",
+    "dateTime": "{day}.{month}.{year} {hour}:{minute}"
+  },
   "doctorReport": {
     "title": "Raport zdrowotny",
     "subtitle": "HealthLog — Osobisty raport zdrowotny",

src/lib/i18n/__tests__/format-locale-order.test.ts

@@ -0,0 +1,69 @@
+/**
+ * v1.4.27 B6 — `format.dateShort` / `timeShort` / `dateTime` ordering.
+ *
+ * Each shipped locale carries a `format.*` namespace that documents
+ * its native date-pattern ordering as i18n strings. The actual
+ * formatting still routes through `Intl.*` via
+ * `src/lib/format-locale.ts`; the format keys exist so downstream
+ * surfaces (PDF export, email templates, CSV docstrings) can render
+ * the date hint without a JS context.
+ *
+ * This smoke test pins the ordering per locale so a copy-paste
+ * regression that flips DD/MM to MM/DD on the French bundle would
+ * fail fast.
+ */
+import { readFileSync } from "node:fs";
+import { join } from "node:path";
+import { describe, expect, it } from "vitest";
+
+const MESSAGES = join(__dirname, "../../../../messages");
+
+function loadFormat(locale: string): {
+  dateShort: string;
+  timeShort: string;
+  dateTime: string;
+} {
+  const bundle = JSON.parse(
+    readFileSync(join(MESSAGES, `${locale}.json`), "utf8"),
+  );
+  const fmt = bundle.format as
+    | { dateShort?: string; timeShort?: string; dateTime?: string }
+    | undefined;
+  if (!fmt || !fmt.dateShort || !fmt.timeShort || !fmt.dateTime) {
+    throw new Error(`Locale ${locale} is missing the format namespace`);
+  }
+  return fmt as { dateShort: string; timeShort: string; dateTime: string };
+}
+
+describe("locale-native format ordering", () => {
+  it("DE renders day-month-year with dot separators", () => {
+    const fmt = loadFormat("de");
+    expect(fmt.dateShort).toBe("{day}.{month}.{year}");
+    expect(fmt.dateTime).toBe("{day}.{month}.{year} {hour}:{minute}");
+    expect(fmt.timeShort).toBe("{hour}:{minute}");
+  });
+
+  it("EN renders month-day-year with slash separators", () => {
+    const fmt = loadFormat("en");
+    expect(fmt.dateShort).toBe("{month}/{day}/{year}");
+    expect(fmt.dateTime).toBe("{month}/{day}/{year} {hour}:{minute}");
+    expect(fmt.timeShort).toBe("{hour}:{minute}");
+  });
+
+  it.each([["fr"], ["es"], ["it"]])(
+    "%s renders day-month-year with slash separators (native ordering)",
+    (locale) => {
+      const fmt = loadFormat(locale);
+      expect(fmt.dateShort).toBe("{day}/{month}/{year}");
+      expect(fmt.dateTime).toBe("{day}/{month}/{year} {hour}:{minute}");
+      expect(fmt.timeShort).toBe("{hour}:{minute}");
+    },
+  );
+
+  it("PL renders day-month-year with dot separators (native ordering)", () => {
+    const fmt = loadFormat("pl");
+    expect(fmt.dateShort).toBe("{day}.{month}.{year}");
+    expect(fmt.dateTime).toBe("{day}.{month}.{year} {hour}:{minute}");
+    expect(fmt.timeShort).toBe("{hour}:{minute}");
+  });
+});