feat(social): per-game friend request to disguised robots + lobby/stats/tile cosmetics

Functional: the in-game add-friend handshake aimed at an auto-match opponent who is
secretly a pooled robot now records the request per (game, seat) in a new
robot_friend_requests table -- never against the shared robot account -- mirroring the
robot_blocks pattern. The shared account stays out of friendships, the "requested" state
is pinned to the seat (not leaked across the player's other games), the robot ignores it,
and a background reaper drops the row 7 days after its game finishes. The outgoing-requests
list carries these per-game rows so the seat control stays disabled across reloads. No
withdraw UI, per owner decision.

Cosmetics:
- Lobby: an in-progress game tints the viewer's own score number green when leading or
  tied, red when trailing (reusing --ok/--danger); scores now render in seat-number order,
  matching the over-the-board scoreboard.
- Stats: the per-variant best move is laid out on two lines -- the variant label, then the
  score (right-aligned in its column) and the word tiles (left-aligned) below it.
- Dark theme: the played-tile background is a touch darker so a player-placed tile reads
  with more contrast (light theme unchanged).

Docs (ARCHITECTURE, FUNCTIONAL + _ru mirror, backend README, UI_DESIGN) updated in the
same change.

ui/src/lib/lobbysort.ts

@@ -12,6 +12,29 @@ export function isMyTurn(game: GameView, myId: string): boolean {
   return (game.status === 'active' || game.status === 'open') && !!me && game.toMove === me.seat;
 }
 
+/**
+ * scoreStanding colours the viewer's own score on an in-progress game: 'win' when leading or
+ * tied (green), 'lose' when trailing (red). It is null for any game that is not active (open or
+ * finished — finished games show the result emoji instead) or where myId is not seated against
+ * an opponent, so the lobby leaves those numbers in the muted default.
+ */
+export function scoreStanding(game: GameView, myId: string): 'win' | 'lose' | null {
+  if (game.status !== 'active') return null;
+  const me = game.seats.find((s) => s.accountId === myId);
+  if (!me) return null;
+  const others = game.seats.filter((s) => s.accountId && s.accountId !== myId).map((s) => s.score);
+  if (!others.length) return null;
+  return me.score >= Math.max(...others) ? 'win' : 'lose';
+}
+
+/**
+ * orderedSeats returns a game's seats in seat-number order (matching the over-the-board
+ * scoreboard), without mutating the source array.
+ */
+export function orderedSeats(game: GameView): GameView['seats'] {
+  return [...game.seats].sort((a, b) => a.seat - b.seat);
+}
+
 /** LobbyPhase is a game's lobby bucket — which of the three card sections it currently sits in. */
 export type LobbyPhase = 'mine' | 'theirs' | 'finished';