Phase 03 — Games, players, and roll history

Everything now persists to Postgres — games, players, and roll history.

Added

• Postgres persistence (Drizzle ORM): games, players, and rolls tables
• Home page rebuilt as a join/create screen — join by 5-character hash (protected games prompt once for a password), or create a new game (name + optional password)
• Password-protected games gated by a signed session cookie; a one-time "here's your hash" dialog after joining/creating
• Game top bar gains a Settings menu (Leave game / Legend / About) and a clickable name (rename, change password, delete, leave)
• Multiple players per game: name, auto-distinct random color, icon, enabled flag; drag-to-reorder player list
• A player bar shows who's active; "Next player" cycles forward (confirmed), picking a specific player from the list goes anywhere (also confirmed); each player's hand is saved and restored independently; dice tint in the current player's color
• Roll history: every roll's sum, per-die breakdown, average, median, min, and max are recorded; a footer bar shows the latest roll, a full history dialog lets you mark rolls invalid without deleting them

See CHANGELOG.md for the complete list.