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>

models/game.py

@@ -28,6 +28,9 @@ class Game(Base):
     id = Column(String(36), primary_key=True, default=lambda: str(uuid.uuid4()))
     category_id = Column(Integer, ForeignKey("categories.id"), nullable=False)
     board_size = Column(Integer, nullable=False, default=10)
+    player_name = Column(
+        String(20), nullable=False, default="Anonymous", server_default="Anonymous"
+    )
     grid = Column(JSON, nullable=False)
     status = Column(String(20), nullable=False, default="in_progress")
     started_at = Column(