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/adapt-recipe-button.tsx

@@ -1,6 +1,7 @@
 "use client";
 
 import { useState } from "react";
+import { useTranslations } from "next-intl";
 import { useRouter } from "next/navigation";
 import { Wand2, Loader2, X } from "lucide-react";
 import { toast } from "sonner";
@@ -26,6 +27,7 @@ export function AdaptRecipeButton({
   recipeId: string;
   ingredients: Ingredient[];
 }) {
+  const t = useTranslations("recipe");
   const router = useRouter();
   const [open, setOpen] = useState(false);
   const [excluded, setExcluded] = useState<Set<string>>(new Set());
@@ -50,7 +52,7 @@ export function AdaptRecipeButton({
 
   async function handleAdapt() {
     if (excluded.size === 0 && !extraConstraints.trim()) {
-      toast.error("Select at least one ingredient to exclude or add a constraint");
+      toast.error(t("adaptConstraintRequired"));
       return;
     }
 
@@ -68,7 +70,7 @@ export function AdaptRecipeButton({
 
       if (!res.ok) {
         const err = await res.json() as { error?: string };
-        toast.error(err.error ?? "Failed to adapt recipe");
+        toast.error(err.error ?? t("adaptFailed"));
         return;
       }
 
@@ -154,7 +156,7 @@ export function AdaptRecipeButton({
                 id="extra-constraints"
                 value={extraConstraints}
                 onChange={(e) => setExtraConstraints(e.target.value)}
-                placeholder="e.g. Make it vegan, lower the calories, use pantry staples only, gluten-free…"
+                placeholder={t("adaptConstraintPlaceholder")}
                 rows={2}
                 disabled={adapting}
               />