security: widen API-key auth to content/AI routes (v0.27.0)

Convert requireSession -> requireSessionOrApiKey across recipes,
collections, meal-plans, shopping-lists, pantry, feed, and ai/*
(52 routes) so API keys work end-to-end, not just for the handful of
endpoints that supported them before. Scope was explicitly confirmed
per-resource-family with the user before any file was touched.

Left session-cookie-only, deliberately: users/me*, ai-keys/*,
webhooks/*, conversations/*, notifications/*, push/subscribe, admin/*
— account/credential-adjacent surface that shouldn't widen without a
separate, explicit decision.

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

apps/web/app/api/v1/ai/adapt/[id]/route.ts

@@ -2,7 +2,7 @@ import { NextRequest, NextResponse } from "next/server";
 import { z } from "zod";
 import { and, eq } from "@epicure/db";
 import { db, recipes, recipeIngredients, recipeSteps } from "@epicure/db";
-import { requireSession } from "@/lib/api-auth";
+import { requireSessionOrApiKey } from "@/lib/api-auth";
 import { withAiQuota, resolveAiConfigOrError } from "@/lib/ai/ai-error";
 import { adaptRecipe } from "@/lib/ai/features/adapt-recipe";
 import { withUserKey } from "@/lib/ai/resolve-user-key";
@@ -18,7 +18,7 @@ const Schema = z.object({
 type Params = { params: Promise<{ id: string }> };
 
 export async function POST(req: NextRequest, { params }: Params) {
-  const { session, response } = await requireSession();
+  const { session, response } = await requireSessionOrApiKey(req);
   if (response) return response;
 
   const { id } = await params;