master
feat: persist game results and update player EXP on game over
docs(IMPROVEMENTS): mark item 6 as done, fix migration comment
add migration 004: role column and refresh_tokens table
refactor: drop unused api_key column and ValidateAPIKey
feat(rating): add player_state.rating migration
feat: add leaderboard endpoint (p.29 IMPROVEMENTS)
feat: add achievements system (p.30 IMPROVEMENTS)
refactor: load achievement definitions from database with periodic reload
feat: player statistics endpoint and lobby stats modal
feat: Telegram Mini App auth via initData
fix: resolve all golangci-lint issues