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/components/RecipeServings.tsx

@@ -1,6 +1,6 @@
 "use client";
 
-import { Flame, Minus, Plus } from "lucide-react";
+import { RiFireLine as Flame, RiSubtractLine as Minus, RiAddLine as Plus } from "@remixicon/react";
 import { useEffect, useRef, useState, useSyncExternalStore } from "react";
 import type { Recipe } from "@/app/types";
 import { RecipeDetail } from "./RecipeDetail";