feat: expand to 1014 words, add title-case display and 2 new themes

- Move word data from hardcoded seed.py to data/words.json
- Expand from 210 words across 7 categories to 1014 words across 14
  categories (animals, food, colors, sports, space, nature, music,
  science, countries, occupations, ocean, weather, mythology, technology)
- Word list sidebar now shows title case (Tiger) while grid stays
  uppercase; text input remains case-insensitive
- Add Ocean theme (light, blue accents) and Forest theme (dark, amber
  accents on deep green)
- Replace hardcoded rgba values with --coral-bg CSS variable so
  selection highlighting adapts per theme

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

templates/game.html

@@ -10,6 +10,14 @@
     <h2 class="mb-4">New Game</h2>
     <div class="card">
         <div class="card-body">
+            <div class="row g-3 mb-3">
+                <div class="col-md-6">
+                    <label for="player-name" class="form-label">Player Name</label>
+                    <input type="text" id="player-name" class="form-control"
+                           placeholder="Anonymous" maxlength="20"
+                           autocomplete="off">
+                </div>
+            </div>
             <div class="row g-3 align-items-end">
                 <div class="col-md-3">
                     <label for="category-select" class="form-label">Category</label>