fix(game): release a banished race's assets during turn generation

TurnWipeExtinctRaces iterated only non-extinct races, so an
administratively banished race (flagged extinct, TTL untouched) was never
wiped: its planets stayed owned and its ships lingered, while the race
itself could no longer act. The loop now covers every race and wipes when
either an active race's TTL has run out (idle / quit) or an extinct race
still holds assets (banish). The asset check makes repeated passes
idempotent.

wipeRace already matched the rules for exclusion (ships removed, planets
uninhabited, industry and capital cleared, material retained), so the
behaviour is just documented in game/README.md.

Tests: banish releases planets and ships on the next turn (and is
idempotent); idle-timeout wipe still fires under the new iterator.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

game/internal/controller/race.go

@@ -117,13 +117,34 @@ func (c *Cache) raceTechLevel(ri int, t game.Tech, v float64) {
 }
 
 func (c *Cache) TurnWipeExtinctRaces() {
-	for i := range c.listRaceActingIdx() {
-		if (c.g.Race[i].Extinct && c.g.Race[i].TTL > 0) || (!c.g.Race[i].Extinct && c.g.Race[i].TTL == 0) {
+	for i := range c.listRaceIdx() {
+		r := &c.g.Race[i]
+		// Idle timeout or voluntary quit: a still-active race whose TTL ran
+		// out. Administrative banish: a race already flagged extinct that
+		// still holds assets to release. Once a race is wiped it owns nothing,
+		// so the asset check keeps this idempotent across later turns.
+		if (!r.Extinct && r.TTL == 0) || (r.Extinct && c.raceHasAssets(i)) {
 			c.wipeRace(i)
 		}
 	}
 }
 
+// raceHasAssets reports whether the race still owns a planet or a ship group.
+func (c *Cache) raceHasAssets(ri int) bool {
+	id := c.g.Race[ri].ID
+	for i := range c.g.Map.Planet {
+		if c.g.Map.Planet[i].OwnedBy(id) {
+			return true
+		}
+	}
+	for i := range c.g.ShipGroups {
+		if c.g.ShipGroups[i].OwnerID == id {
+			return true
+		}
+	}
+	return false
+}
+
 func (c *Cache) wipeRace(ri int) {
 	c.validateRaceIndex(ri)
 	r := &c.g.Race[ri]