fix(i18n): translate remaining recipe card/detail strings, localize AI responses

Recipe cards, the recipe detail page, and meal planner still rendered raw
"{n} servings"/"{n}m cook"/"{n} srv" text and untranslated difficulty labels
outside the earlier i18n pass. Also wires the user's locale into AI features
that previously always answered in English regardless of app language:
recipe chat, ingredient substitution, recipe ideas, and generate-from-idea.
The recipe-language picker in the AI generate dialog now defaults to the
user's locale instead of always defaulting to English.

apps/web/app/(app)/recipes/[id]/page.tsx

@@ -28,7 +28,7 @@ import { CommentsSection } from "@/components/social/comments-section";
 import { getPublicUrl } from "@/lib/storage";
 import { cn } from "@/lib/utils";
 import { RecipeChatPanel } from "@/components/recipe/recipe-chat-panel";
-import { getMessages } from "@/lib/i18n/server";
+import { getMessages, formatMessage } from "@/lib/i18n/server";
 
 type Params = { params: Promise<{ id: string }> };
 
@@ -175,26 +175,26 @@ export default async function RecipePage({ params }: Params) {
 
         <div className="flex flex-wrap items-center gap-3 text-sm">
           {recipe.difficulty && (
-            <Badge variant={DIFFICULTY_COLOR[recipe.difficulty]}>{recipe.difficulty}</Badge>
+            <Badge variant={DIFFICULTY_COLOR[recipe.difficulty]}>{m.recipe.difficulty[recipe.difficulty]}</Badge>
           )}
           <span className="flex items-center gap-1 text-muted-foreground">
             <Users className="h-4 w-4" />
-            {recipe.baseServings} servings
+            {formatMessage(m.recipe.servings, { count: recipe.baseServings })}
           </span>
           {recipe.prepMins && (
             <span className="flex items-center gap-1 text-muted-foreground">
               <Clock className="h-4 w-4" />
-              {recipe.prepMins}m prep
+              {formatMessage(m.recipe.prep, { mins: recipe.prepMins })}
             </span>
           )}
           {recipe.cookMins && (
             <span className="flex items-center gap-1 text-muted-foreground">
               <ChefHat className="h-4 w-4" />
-              {recipe.cookMins}m cook
+              {formatMessage(m.recipe.cook, { mins: recipe.cookMins })}
             </span>
           )}
           {totalMins > 0 && recipe.prepMins && recipe.cookMins && (
-            <span className="text-muted-foreground">({totalMins}m total)</span>
+            <span className="text-muted-foreground">({formatMessage(m.recipe.total, { mins: totalMins })})</span>
           )}
           <span className="flex items-center gap-1 text-muted-foreground ml-auto">
             <VisibilityIcon className="h-4 w-4" />