feedback1c WJ: ticker queue helpers; a newer leader-damage line replaces the older one

Review follow-up for the Hidden Core broadcast fix. The strip's queue rules are
now pure, exported helpers (tickerSupersedes, enqueueTickerLines,
pruneTickerLines, nextTickerLine) with unit tests across a round 14 -> 15
change, instead of source regex checks only.

A player's newer BOSS_HIT line of the same round replaces their older one,
queued or on screen (it names a higher threshold), so a burst finish shows its
highest milestone before the round ends and the last round's lines are dropped.
Lines now carry playerId from main.js. The solo match test is labelled 绝境
(HARD), the difficulty it runs.

docs/META.md

@@ -595,7 +595,8 @@ result may only name the unit types its lineup can field, fields.js validateClie
 current leader per player, each threshold once per boss round: the player's damage to that round's shared pool,
 `SharedBossPool.byPlayer`, over its size — the Final Assault and the Hidden Core count apart, while `stats.bossDamage`,
 the result's 领袖伤害, adds both up; the browser's strip, which plays its queue 5.2 s per line, drops a BOSS_HIT line
-once the round it came in is over — public/js/ui/ticker.js `tickerLineLive`), CHAR_GIFT (to the receiver only), plus
+once the round it came in is over, and a player's newer BOSS_HIT line of the round replaces their older one, queued or
+on screen — public/js/ui/ticker.js `tickerLineLive`, `tickerSupersedes`), CHAR_GIFT (to the receiver only), plus
 CUSTOM texts (eliminations, 联防, hidden core).
 
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