v3.0.0: V3 features, server refactoring, and documentation overhaul

- Extract WebSocket handlers from main.py into handlers.py
- Add V3 feature docs (dealer rotation, dealing animation, round end reveal,
  column pair celebration, final turn urgency, opponent thinking, score tallying,
  card hover/selection, knock early drama, column pair indicator, swap animation
  improvements, draw source distinction, card value tooltips, active rules context,
  discard pile history, realistic card sounds)
- Add V3 refactoring docs (ai.py, main.py/game.py, misc improvements)
- Add installation guide with Docker, systemd, and nginx setup
- Add helper scripts (install.sh, dev-server.sh, docker-build.sh)
- Add animation flow diagrams documentation
- Add test files for handlers, rooms, and V3 features
- Add e2e test specs for V3 features
- Update README with complete project structure and current tech stack
- Update CLAUDE.md with full architecture tree and server layer descriptions
- Update .env.example to reflect PostgreSQL (remove SQLite references)
- Update .gitignore to exclude virtualenv files, .claude/, and .db files
- Remove tracked virtualenv files (bin/, lib64, pyvenv.cfg)
- Remove obsolete game_log.py (SQLite) and games.db

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

client/index.html

@@ -282,7 +282,11 @@
                         </div>
                         <div class="header-col header-col-center">
                             <div id="status-message" class="status-message"></div>
-                            <div id="final-turn-badge" class="final-turn-badge hidden">⚡ FINAL TURN</div>
+                            <div id="final-turn-badge" class="final-turn-badge hidden">
+                                <span class="final-turn-icon">⚡</span>
+                                <span class="final-turn-text">FINAL TURN</span>
+                                <span class="final-turn-remaining"></span>
+                            </div>
                         </div>
                         <div class="header-col header-col-right">
                             <span id="game-username" class="game-username hidden"></span>