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>

package.json

@@ -10,10 +10,13 @@
     "test": "bun test"
   },
   "dependencies": {
-    "lucide-react": "^1.66.0",
+    "@remixicon/react": "^4.9.0",
+    "jspdf": "^4.2.1",
     "next": "16.4.3",
     "react": "19.3.0",
-    "react-dom": "19.3.0"
+    "react-aria-components": "^1.22.1",
+    "react-dom": "19.3.0",
+    "tailwind-merge": "^3.7.0"
   },
   "devDependencies": {
     "@tailwindcss/turbopack": "^4",