feat(i18n): translate hardcoded strings across print, public recipe, and recipe management UI

Wires dozens of components and server pages to next-intl instead of hardcoded
English text, and adds a lightweight getMessages/formatMessage helper for
server components (print pages, public recipe page, cook metadata) since
next-intl/server isn't wired into this app's routing. Backfills missing
en/fr message keys that existing code already referenced but fr.json lacked.

apps/web/components/recipe/serving-scaler.tsx

@@ -1,6 +1,7 @@
 "use client";
 
 import { useState } from "react";
+import { useTranslations } from "next-intl";
 import { Minus, Plus, Sparkles, X } from "lucide-react";
 import { Button } from "@/components/ui/button";
 import { scaleQuantity, hasQuantity } from "@/lib/fractions";
@@ -35,6 +36,7 @@ export function ServingScaler({
   recipeId?: string;
   onAiScale?: (ingredients: ScaledIngredient[] | null) => void;
 }) {
+  const t = useTranslations("servingScaler");
   const [servings, setServings] = useState(baseServings);
   const [aiScaledIngredients, setAiScaledIngredients] = useState<ScaledIngredient[] | null>(null);
   const [aiScaling, setAiScaling] = useState(false);
@@ -67,7 +69,7 @@ export function ServingScaler({
   return (
     <div className="space-y-4">
       <div className="flex items-center gap-3 flex-wrap">
-        <span className="text-sm font-medium text-muted-foreground">Servings</span>
+        <span className="text-sm font-medium text-muted-foreground">{t("servings")}</span>
         <div className="flex items-center gap-2">
           <Button
             variant="outline"
@@ -94,7 +96,7 @@ export function ServingScaler({
             className="text-xs text-muted-foreground hover:text-foreground underline"
             onClick={() => setServings(baseServings)}
           >
-            reset
+            {t("reset")}
           </button>
         )}
         {recipeId && servings !== baseServings && (
@@ -106,7 +108,7 @@ export function ServingScaler({
             disabled={aiScaling}
           >
             <Sparkles className="h-3 w-3" />
-            {aiScaling ? "Scaling…" : "AI Scale"}
+            {aiScaling ? t("scaling") : t("aiScale")}
           </Button>
         )}
       </div>
@@ -114,7 +116,7 @@ export function ServingScaler({
       {aiScaledIngredients && (
         <div className="flex items-center gap-2 text-xs text-muted-foreground">
           <Sparkles className="h-3 w-3 shrink-0" />
-          <span>AI-scaled quantities shown below</span>
+          <span>{t("aiScaledNote")}</span>
           <button
             className="ml-auto hover:text-foreground"
             onClick={dismissAiScale}