refactor: move shared modules out of app/

`app/` should hold route segments only. Game logic and the player-card
component are imported by both routes, so they belong outside:

  app/loto-game-logic.ts   -> lib/game-logic.ts
  app/loto-player-board.tsx -> components/player-board.tsx

Imports use the existing @/* alias. Drops the redundant `loto-` prefix.
Also fixes the package name from the scaffold default.

web/docs/system-architecture.md

@@ -88,7 +88,7 @@ All pages use `"use client"` because:
 Files with `"use client"`:
 - `app/page.tsx`
 - `app/master/page.tsx`
-- `app/loto-player-board.tsx`
+- `components/player-board.tsx`
 
 ## Data Flow: Mark a Cell