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>

.gitignore

@@ -188,6 +188,19 @@ cython_debug/
 #  you could uncomment the following to ignore the entire vscode folder
 # .vscode/
 
+# Claude Code
+.claude/
+
+# Virtualenv in project root
+bin/
+pyvenv.cfg
+
+# Database files
+*.db
+
+# Personal notes
+lookfah.md
+
 # Ruff stuff:
 .ruff_cache/