feat: manual nutrition entry on recipe editor

Lets authors enter nutrition values by hand instead of relying only on
the AI estimate; the detail-page panel now shows whether data was
manually entered or AI-estimated and offers to switch between them.

v0.35.0

apps/web/app/api/v1/recipes/route.ts

@@ -60,6 +60,17 @@ const CreateRecipeSchema = z.object({
     freezerNote: z.string().max(300).optional(),
     dayOfInstructions: z.string().min(1).max(1000),
   })).max(10).default([]),
+  // Manually-entered per-serving nutrition — takes precedence over (and
+  // disables) the AI-estimate action on the recipe page, since re-estimating
+  // would silently discard values the author entered on purpose.
+  nutrition: z.object({
+    calories: z.number().min(0).max(10000),
+    proteinG: z.number().min(0).max(1000),
+    carbsG: z.number().min(0).max(1000),
+    fatG: z.number().min(0).max(1000),
+    fiberG: z.number().min(0).max(1000),
+    sodiumMg: z.number().min(0).max(100000),
+  }).optional(),
 });
 
 export async function GET(req: NextRequest) {
@@ -132,6 +143,8 @@ export async function POST(req: NextRequest) {
       language: data.language,
       sourceUrl: data.sourceUrl,
       isBatchCook: data.isBatchCook,
+      nutritionData: data.nutrition ? { perServing: data.nutrition } : undefined,
+      nutritionManual: !!data.nutrition,
       createdAt: now,
       updatedAt: now,
     });