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/search/explore-page-content.tsx

@@ -8,6 +8,7 @@ import { Button } from "@/components/ui/button";
 import { Badge } from "@/components/ui/badge";
 import { Select, SelectContent, SelectItem, SelectTrigger, SelectValue } from "@/components/ui/select";
 import { Flame, Clock, ChefHat, Search, Sparkles, Wand2, ArrowRight } from "lucide-react";
+import { useTranslations } from "next-intl";
 import type { RecipeResult as ExploreRecipeResult } from "@/app/(app)/explore/page";
 
 const DIFFICULTY_COLORS: Record<string, string> = {
@@ -100,6 +101,8 @@ type Props = {
 export function ExplorePageContent({ trending, recent, initialQuery }: Props) {
   const router = useRouter();
   const searchParams = useSearchParams();
+  const t = useTranslations("explore");
+  const tCommon = useTranslations("common");
 
   const [inputValue, setInputValue] = useState(initialQuery);
   const [query, setQuery] = useState(initialQuery);
@@ -243,7 +246,7 @@ export function ExplorePageContent({ trending, recent, initialQuery }: Props) {
             ref={inputRef}
             value={inputValue}
             onChange={(e) => handleInputChange(e.target.value)}
-            placeholder="Search public recipes…"
+            placeholder={t("searchPlaceholder")}
             className="pl-10 h-12 text-base"
             autoFocus={!!initialQuery}
           />
@@ -253,7 +256,7 @@ export function ExplorePageContent({ trending, recent, initialQuery }: Props) {
           <div className="flex flex-wrap items-center gap-3">
             <Select value={difficulty} onValueChange={handleDifficultyChange}>
               <SelectTrigger className="w-40">
-                <SelectValue placeholder="Difficulty" />
+                <SelectValue placeholder={tCommon("difficulty")} />
               </SelectTrigger>
               <SelectContent>
                 <SelectItem value="any">Any difficulty</SelectItem>
@@ -265,7 +268,7 @@ export function ExplorePageContent({ trending, recent, initialQuery }: Props) {
             <Input
               type="number"
               min={1}
-              placeholder="Max minutes"
+              placeholder={t("maxMinutes")}
               value={maxMins}
               onChange={(e) => handleMaxMinsChange(e.target.value)}
               className="w-36"
@@ -342,7 +345,7 @@ export function ExplorePageContent({ trending, recent, initialQuery }: Props) {
               <Input
                 value={ideasPrompt}
                 onChange={(e) => setIdeasPrompt(e.target.value)}
-                placeholder="e.g. quick weeknight dinners, Italian comfort food…"
+                placeholder={t("aiSearchPlaceholder")}
                 className="bg-background"
               />
               <Button type="submit" disabled={ideasLoading} variant="secondary" className="shrink-0">