feat: misc — cooking mode, OpenAPI docs, email, storage, upload, homepage

Cooking mode step-by-step view. OpenAPI 3.1 spec auto-generated from Zod schemas.
Email lib (resend). Redis client. S3 storage helper. Photo upload endpoint.
Landing page. Short recipe URL redirect /r/[id]. API docs page.

apps/web/app/api/v1/openapi.json/route.ts

@@ -0,0 +1,8 @@
+import { generateOpenApiSpec } from "@/lib/openapi";
+
+export async function GET() {
+  const spec = generateOpenApiSpec();
+  return Response.json(spec, {
+    headers: { "Access-Control-Allow-Origin": "*" },
+  });
+}