games: UNO becomes a table you sit at, and the pot that pays whoever goes out first

Phase D backend: UNO is now a session like hold'em, not a single stake. You sit
with a buy-in stack, ante into a pot each hand, and leave with what's in front of
you. The engine lost its `You` constant and its measured multiples: ApplyMove
takes the acting seat, New takes a seat list, a Tier carries an ante instead of a
Base, and a hand settles by moving the pot to the winner (less rake, and never
when a bot takes it) rather than paying a multiple. A mercy kill puts a seat out
of the hand, not out of the game — the last one standing takes the pot.

The redaction moved to the web layer, where hold'em's already lives: the engine
now stamps every seat's hand onto its events, and viewUno/viewUnoEvents strip
everything that isn't the viewer's own. TestUnoViewNeverLeaksAnotherSeatsCards is
the wall. unoTable implements tableGame; /uno/{sit,move,leave,tables,stream,chat,
say} mirror hold'em, with stream/chat/say now shared game-agnostic handlers.

The frontend is not done: uno.js still calls the retired solo endpoint, so the
page renders but is not yet playable. All engine and web tests are green.

Claude-Session: https://claude.ai/code/session_013M5nD7PgUboJXoDcYHzpuJ

internal/games/uno/bot.go

@@ -173,17 +173,9 @@ func botColor(hand []Card, rng *rand.Rand) Color {
 	return best
 }
 
-// botNames deals the bots their names. Flavour, and load-bearing flavour: "Kiwi
-// played a +4" is a table, "Bot 2 played a +4" is a test fixture.
-func botNames(n int, rng *rand.Rand) []string {
-	pool := append([]string(nil), botPool...)
-	rng.Shuffle(len(pool), func(i, j int) { pool[i], pool[j] = pool[j], pool[i] })
-	if n > len(pool) {
-		n = len(pool)
-	}
-	return pool[:n]
-}
-
+// botPool are the regulars a bot seat is named from. Flavour, and load-bearing
+// flavour: "Kiwi played a +4" is a table, "Bot 2 played a +4" is a test fixture.
+// More names than a full table, so no two chairs ever share one.
 var botPool = []string{
 	"Kiwi", "Mochi", "Bramble", "Pixel", "Gus", "Nori", "Waffle", "Marzipan",
 	"Tuck", "Bebop", "Olive", "Rascal", "Peaches", "Dot", "Sable", "Clementine",