fix: audit fixes — tier-quota bypass, webhook SSRF, auth hardening, pagination, a11y

Full audit (bugs/UI-UX/backend/feature-gap) turned up a money-leak AI quota
bypass, webhook SSRF, and a long tail of missing pagination/auth/a11y work.
Fixes land together since HANDOFF.md tracked them as one backlog.

- AI routes charge tier quota before generating; nutrition POST is author-only
- Webhook dispatch re-validates URL per delivery (SSRF/DNS-rebinding), treats
  redirects as failures; recipe.published now actually dispatches
- New indexes/unique constraints on recipes, meal-planning, comments FK cascade
- Recipe PUT/restore snapshot only inside the transaction, after validation
- Recipe DELETE cleans up S3 objects (recipe + review photos)
- Optimistic UI (favorite/star/follow/shopping-list) rolls back on failure
- Upload presign enforces file size cap + per-tier storage quota
- Route-level loading/error/not-found states across (app), admin, and root
- middleware.ts guards (app)/admin; requireAdmin checks DB role, not cached
  session; rate limiting applied to both session and API-key branches,
  bucketed per key; Stripe webhook dedupes by event id
- Pagination added to recipes, feed, profile, comments, pantry, admin tables
- Nav shows real avatar + profile link + dark-mode toggle; destructive actions
  standardized on AlertDialog
- Unsaved-changes guard + real ingredient/step validation on recipe form;
  canonical /recipes/[id] used in-app; next/image migration; aria-labels and
  alt text across icon buttons, avatars, recipe photos
- packages/api-types removed (zero callers, too drifted to safely rewire);
  openapi.ts and ai-keys error shape drift fixed; BYOK decrypt failures now
  surface instead of silently falling back to the platform key

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

apps/web/app/api/v1/ai/substitute/route.ts

@@ -1,7 +1,7 @@
 import { NextRequest, NextResponse } from "next/server";
 import { z } from "zod";
 import { requireSession } from "@/lib/api-auth";
-import { withAiQuota } from "@/lib/ai/ai-error";
+import { withAiQuota, resolveAiConfigOrError } from "@/lib/ai/ai-error";
 import { applyRateLimit } from "@/lib/rate-limit";
 import { getDefaultProviderWithKey } from "@/lib/ai/resolve-user-key";
 import { substituteIngredient } from "@/lib/ai/features/substitute-ingredient";
@@ -28,9 +28,14 @@ export async function POST(req: NextRequest) {
     ? `recipe "${parsed.data.recipeTitle}"`
     : "a general recipe";
 
-  const aiConfig = parsed.data.provider
-    ? { provider: parsed.data.provider, model: parsed.data.model }
-    : await getDefaultProviderWithKey(session!.user.id);
+  let aiConfig;
+  if (parsed.data.provider) {
+    aiConfig = { provider: parsed.data.provider, model: parsed.data.model };
+  } else {
+    const configResult = await resolveAiConfigOrError(() => getDefaultProviderWithKey(session!.user.id));
+    if (!configResult.ok) return configResult.response;
+    aiConfig = configResult.data;
+  }
 
   const locale = (session!.user as { locale?: string }).locale ?? "en";