Move UI to BoardUI with slate + salmon theme; add PDF plan export

- Adopt BoardUI (Pro init): theme tokens, Inter, .dark mode, Button,
  SegmentedControl, Meter, Skeleton and ThemeToggle; remap the app's
  color aliases onto BoardUI tokens and swap lucide for Remix icons
- Retint BoardUI's neutral ramp to cool slate with a salmon accent;
  drop the dotted background; raise muted text contrast
- Simplify the landing page and remove the overlap explorer
- Planner: explicit "I have this" toggle on grocery lines, pantry panel
  above the menu with the staples list spelled out, sticky aisle
  header fix, and a "Download PDF" plan export (jsPDF, lazy-loaded)
- Recipes: replace the family cabbage soup with Cade's Cabbage Soup
  (adds Bone-In Ham Steak to the catalog); remove Ham, Bean & Cabbage Soup
- Remove unused BoardUI components, dependencies and exports

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

app/caydens-corner/page.tsx

@@ -1,4 +1,4 @@
-import { ArrowRight, BookHeart } from "lucide-react";
+import { RiArrowRightLine as ArrowRight, RiHeart3Line as BookHeart } from "@remixicon/react";
 import type { Metadata } from "next";
 import Link from "next/link";
 import { ViewTransition } from "react";
@@ -26,7 +26,7 @@ export default function CaydensCornerPage() {
     <div className="min-h-dvh">
       <SiteHeader active="caydens-corner" />
       <main className="mx-auto max-w-7xl px-4 py-10 sm:px-6">
-        <section className="paper-grain rounded-2xl border border-brand-border bg-brand-950 px-6 py-10 sm:px-10">
+        <section className="rounded-2xl border border-brand-border bg-brand-950 px-6 py-10 sm:px-10">
           <p className="inline-flex items-center gap-2 font-mono text-xs font-semibold tracking-widest text-brand-300 uppercase">
             <BookHeart className="size-4" strokeWidth={2} aria-hidden />
             Cayden&apos;s Corner · Heirloom Cookbook
@@ -69,7 +69,7 @@ export default function CaydensCornerPage() {
                   <li key={r.id}>
                     <Link
                       href={`/recipes/${r.id}`}
-                      className="group flex h-full flex-col rounded-xl border border-line bg-surface p-4 transition-colors hover:border-line-strong hover:bg-raised/60"
+                      className="group flex h-full flex-col rounded-3xl border border-border-button-default bg-surface p-4 transition-colors hover:border-line-strong hover:bg-raised/60"
                     >
                       <ViewTransition name={`recipe-title-${r.id}`}>
                         <span className="font-serif text-lg leading-snug font-semibold text-ink group-hover:text-brand-300">