feat: private accounts, explore/people merge, meal-plan fixes, i18n and theme cleanup

- Private accounts: users.isPrivate hides a user from search and their
  recipes from search/trending/for-you discovery surfaces (follow-aware
  where the route already has session context, blanket exclusion where it
  doesn't); existing followers and direct links are unaffected, no
  follow-request approval flow was built (explicit scope limit)
- Merged /people into the Explore tab (tab=people query param); the old
  standalone route now redirects there
- "Get Ideas" vs "Surprise Me" were doing the same empty-prompt call;
  Surprise Me now injects a real random constraint (5-ingredient, one-pot,
  etc.), matching the existing pattern in the AI recipe-generate dialog
- Meal-plan day cells now link to their recipe (was dead text) and gained
  a one-click "mark as cooked" action
- Theme toggle is now a real three-way light/dark/system control instead
  of a binary flip
- Nutrition goals form had zero i18n wiring; fully localized now

New migration 0027 (users.is_private) generated, left unapplied like the
others. Verified with typecheck, lint, and a clean --no-cache docker build.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

apps/web/components/nutrition/nutrition-goals-form.tsx

@@ -2,6 +2,7 @@
 
 import { useState } from "react";
 import { toast } from "sonner";
+import { useTranslations } from "next-intl";
 import { Button } from "@/components/ui/button";
 import { Input } from "@/components/ui/input";
 import { Label } from "@/components/ui/label";
@@ -18,6 +19,7 @@ interface NutritionGoalsFormProps {
 }
 
 export function NutritionGoalsForm({ initialGoals }: NutritionGoalsFormProps) {
+  const t = useTranslations("settings.nutritionGoals");
   const [caloriesKcal, setCaloriesKcal] = useState<string>(
     initialGoals?.caloriesKcal != null ? String(initialGoals.caloriesKcal) : ""
   );
@@ -50,13 +52,13 @@ export function NutritionGoalsForm({ initialGoals }: NutritionGoalsFormProps) {
       });
 
       if (!res.ok) {
-        toast.error("Failed to save nutrition goals");
+        toast.error(t("saveError"));
         return;
       }
 
-      toast.success("Nutrition goals saved");
+      toast.success(t("saveSuccess"));
     } catch {
-      toast.error("Failed to save nutrition goals");
+      toast.error(t("saveError"));
     } finally {
       setSaving(false);
     }
@@ -66,52 +68,52 @@ export function NutritionGoalsForm({ initialGoals }: NutritionGoalsFormProps) {
     <form onSubmit={handleSubmit} className="space-y-4">
       <div className="grid grid-cols-2 gap-4">
         <div className="space-y-2">
-          <Label htmlFor="caloriesKcal">Calories (kcal/day)</Label>
+          <Label htmlFor="caloriesKcal">{t("caloriesLabel")}</Label>
           <Input
             id="caloriesKcal"
             type="number"
             min={0}
             value={caloriesKcal}
             onChange={(e) => setCaloriesKcal(e.target.value)}
-            placeholder="e.g. 2000"
+            placeholder={t("caloriesPlaceholder")}
           />
         </div>
         <div className="space-y-2">
-          <Label htmlFor="proteinG">Protein (g/day)</Label>
+          <Label htmlFor="proteinG">{t("proteinLabel")}</Label>
           <Input
             id="proteinG"
             type="number"
             min={0}
             value={proteinG}
             onChange={(e) => setProteinG(e.target.value)}
-            placeholder="e.g. 50"
+            placeholder={t("proteinPlaceholder")}
           />
         </div>
         <div className="space-y-2">
-          <Label htmlFor="carbsG">Carbs (g/day)</Label>
+          <Label htmlFor="carbsG">{t("carbsLabel")}</Label>
           <Input
             id="carbsG"
             type="number"
             min={0}
             value={carbsG}
             onChange={(e) => setCarbsG(e.target.value)}
-            placeholder="e.g. 250"
+            placeholder={t("carbsPlaceholder")}
           />
         </div>
         <div className="space-y-2">
-          <Label htmlFor="fatG">Fat (g/day)</Label>
+          <Label htmlFor="fatG">{t("fatLabel")}</Label>
           <Input
             id="fatG"
             type="number"
             min={0}
             value={fatG}
             onChange={(e) => setFatG(e.target.value)}
-            placeholder="e.g. 70"
+            placeholder={t("fatPlaceholder")}
           />
         </div>
       </div>
       <Button type="submit" disabled={saving}>
-        {saving ? "Saving..." : "Save goals"}
+        {saving ? t("saving") : t("saveButton")}
       </Button>
     </form>
   );