Release 0.15.0

Summary

Gameplay: A Tenhou-style start screen with an OK button holds the first deal until every human seat confirms (or a 10 s timeout), which also unlocks browser sound; AI player turns are paced at 1 s so humans can follow consecutive AI discards. Replays stay unpaced and identical. Bots must now confirm the first deal (GAME_START_CONFIRM).
Localization: The game client is now translated into English, Japanese and Russian — mahjong terms, play screen, result screens and replay pages — with a language switch in the settings menu that redraws in place and shares the lobby's language cookie. Wording, plurals, list joins and decimals follow each language and the glossary.
Browser support: Browsers too old to lay out the board (before Chrome/Edge 108, Firefox 128, Safari 16.4) get a notice on the game page and a banner in the lobby instead of a broken board; the notice also works on Safari before 15.4.
Frontend: The page body follows the visible viewport height, so phones no longer scroll past the board; sound unlocks without navigator.userActivation, retries failed loads and drops late plays instead of bursting a backlog; the language buttons meet the 40 px tap target; the footer version links to its GitHub release.

feat: link the footer version to its GitHub release (45bedb9)
feat: language switch in the game client's menu (77f658a)
feat: translate the game client's replay pages (72611de)
feat: translate the game client's result screens (b108d92)
feat: translate the game client's play screen (8da3bd5)
feat: translate mahjong terms in the game client (5edd1f2)
feat: translation foundation for the game client (ab8b9da)
feat: notice for browsers too old to lay out the game board (3e6eaf6)
feat: game start screen waits for every OK, pace AI player turns (7c10a80)

bug: language buttons meet the 40px target and show state without colour (23b33e9)
bug: clearer replay summaries across languages (cedf2b7)
bug: fix result-screen wording and decimals per language (b5b7816)
bug: tidy play-screen wording and joins across languages (a1655b4)
bug: grammatical ru tile-action labels, stricter vocabulary tests (35f5341)
bug: keep the old-browser notice working and tidy i18n docs (73331dd)
bug: size the page body by the visible viewport height (c73554f)
bug: sound improvements (0328438)

Code changes (lock files and SVG assets excluded): 218 files changed, 5987 insertions(+), 1941 deletions(-)