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/settings/model-prefs-form.tsx

@@ -14,6 +14,7 @@ import {
   SelectValue,
 } from "@/components/ui/select";
 import { toast } from "sonner";
+import { useTranslations } from "next-intl";
 
 type Provider = "openai" | "anthropic" | "openrouter" | "ollama" | "";
 
@@ -59,6 +60,7 @@ type Prefs = {
 };
 
 export function ModelPrefsForm({ initialPrefs }: { initialPrefs: Prefs | null }) {
+  const t = useTranslations("settingsForm");
   const [prefs, setPrefs] = useState<Prefs>(initialPrefs ?? {});
   const [saving, setSaving] = useState(false);
 
@@ -75,9 +77,9 @@ export function ModelPrefsForm({ initialPrefs }: { initialPrefs: Prefs | null })
         body: JSON.stringify(prefs),
       });
       if (!res.ok) throw new Error("Save failed");
-      toast.success("Model preferences saved");
+      toast.success(t("modelSaved"));
     } catch {
-      toast.error("Failed to save");
+      toast.error(t("modelSaveFailed"));
     } finally {
       setSaving(false);
     }
@@ -132,7 +134,7 @@ export function ModelPrefsForm({ initialPrefs }: { initialPrefs: Prefs | null })
                     onValueChange={(v) => setField(modelKey, v === "default" ? null : v)}
                   >
                     <SelectTrigger className="h-8 text-sm">
-                      <SelectValue placeholder="Default" />
+                      <SelectValue placeholder={t("modelDefaultPlaceholder")} />
                     </SelectTrigger>
                     <SelectContent>
                       <SelectItem value="default">
@@ -149,7 +151,7 @@ export function ModelPrefsForm({ initialPrefs }: { initialPrefs: Prefs | null })
                 ) : (
                   <Input
                     className="h-8 text-sm"
-                    placeholder={provider ? "e.g. llama3.2" : "—"}
+                    placeholder={provider ? t("modelNamePlaceholder") : "—"}
                     value={model}
                     onChange={(e) => setField(modelKey, e.target.value)}
                     disabled={!provider}