Refactor site structure and add comprehensive interactive index

- Move Puzzles and Miscellany under Themes
- Add Contest Problems as new theme
- Create About page with comprehensive site information
- Create InteractiveIndex component with advanced filtering and sorting
- Update navigation to include Index, Themes, and About
- Add pagination (10 items per page) with search and tag filtering
- Update routing structure for new theme organization
- Remove standalone Puzzles and Miscellany pages
- Add new theme pages: /themes/puzzles, /themes/miscellany, /themes/contest-problems
- Update homepage to point to new interactive index
- Maintain consistent layout and styling across all new pages

src/App.tsx

@@ -4,15 +4,18 @@ import { TooltipProvider } from "@/components/ui/tooltip";
 import { QueryClient, QueryClientProvider } from "@tanstack/react-query";
 import { BrowserRouter, Routes, Route } from "react-router-dom";
 import Index from "./pages/Index";
+import InteractiveIndex from "./components/InteractiveIndex";
 import Themes from "./pages/Themes";
-import Puzzles from "./pages/Puzzles";
-import Miscellany from "./pages/Miscellany";
+import About from "./pages/About";
 import DiscreteMath from "./pages/theme-pages/DiscreteMath";
 import SocialChoice from "./pages/theme-pages/SocialChoice";
 import AdvancedAlgorithms from "./pages/theme-pages/AdvancedAlgorithms";
 import DataStructures from "./pages/theme-pages/DataStructures";
 import Games from "./pages/theme-pages/Games";
 import CardsMath from "./pages/theme-pages/CardsMath";
+import Puzzles from "./pages/theme-pages/Puzzles";
+import Miscellany from "./pages/theme-pages/Miscellany";
+import ContestProblems from "./pages/theme-pages/ContestProblems";
 import BinaryNumberGamePage from "./pages/BinaryNumberGamePage";
 import BinaryNumberGameGreenScreen from "./pages/BinaryNumberGameGreenScreen";
 import BinarySearchTrickPage from "./pages/BinarySearchTrickPage";
@@ -38,9 +41,9 @@ const App = () => (
       <BrowserRouter>
         <Routes>
           <Route path="/" element={<Index />} />
+          <Route path="/index" element={<InteractiveIndex />} />
           <Route path="/themes" element={<Themes />} />
-          <Route path="/puzzles" element={<Puzzles />} />
-          <Route path="/miscellany" element={<Miscellany />} />
+          <Route path="/about" element={<About />} />
           
           {/* Theme-specific routes */}
           <Route path="/themes/discrete-math" element={<DiscreteMath />} />
@@ -56,6 +59,9 @@ const App = () => (
           <Route path="/themes/data-structures" element={<DataStructures />} />
           <Route path="/themes/games" element={<Games />} />
           <Route path="/themes/cards-math" element={<CardsMath />} />
+          <Route path="/themes/puzzles" element={<Puzzles />} />
+          <Route path="/themes/miscellany" element={<Miscellany />} />
+          <Route path="/themes/contest-problems" element={<ContestProblems />} />
           
           {/* Direct interactive routes */}
           <Route path="/binary-number-game" element={<BinaryNumberGamePage />} />