feedback1 cell: a 突变细胞 transformation gains the new operator into the 整备区 and frees the carrier's tile (pointed out in PR #2)

Official gameplay footage (bilibili BV1vzyVBuEN9 at about 8:24, BV1Qkw1zMEoR at about 7:25) shows the
next prep with the carrier's tile empty, one more deployment left, and the returned equipment plus the
new tier+1 operator on the bench, deployed by hand afterwards. That is the PRTS 备注 read as written
("生效时，原干员销毁，获得一名高一阶的随机初始干员"): a destroy followed by a gain. The closed PR #2 made
the same claim from a playtest.

- PlayerState.transformChess: the carrier is destroyed wherever it stands (board tile freed, summons
  removed, copies back to the pool); its equipment, the cell included, returns to the hand first
  (overflow temp, auto-merge); then the new operator is gained through acquireChess like any gained
  operator (hand, overflow temp, the no-room rule of every gain; no summon card until it is deployed).
  The returnItems option is gone (the cell's built-in was its only caller).
- A merge the gain completes merges like any gained copy: the elite takes a consumed deployed copy's
  tile, else the hand. _mergeChess loses fromKey / fromDir, so the destroyed carrier's tile never
  counts (PR #2 had kept that path; not adopted); audit.js drops its exception for it.
- builtinMeta, ctx.transform, items/meta.js and bot.js comments follow. Bots and AI 托管 deploy the
  gained operator in their normal lineup step (no bot change needed; a real co-op round pins it).
- ITEM_RULES note and implFormula for the item card; data/items.json rebuilt with build-data --offline.
- Tests: facing, merge, playtest6-elite-to-board and items no longer pin the kept tile; feedback1-meta
  covers a deployed and a bench carrier, hand full -> temp, hand and temp full, a merge with and
  without a deployed copy (never the carrier's tile), 商业包装方案's count on the returned item, and bots /
  AI 托管 redeploying; feedback1-cell checks the new note.

server/match/effectsMeta.js

@@ -24,9 +24,9 @@
 // Items: onEquip / onArt / onDestroy go to the item's own handler only; every other hook runs for items equipped on
 // owned chess (ev.source.holder). That step walks a snapshot — the owned chess and each holder's items as they stand
 // when it begins — and runs an item only if, when its turn comes, it is still equipped on that holder and the holder
-// is still owned: handlers move and destroy pieces mid-walk (突变细胞 transforms its holder and returns the equipment
-// to the hand; normal 博士投影 destroys itself, which splices holder.items), and a live walk skipped the next item or
-// ran it with a holder that was gone. Pieces gained or equipped during the walk wait for the next dispatch.
+// is still owned: handlers move and destroy pieces mid-walk (突变细胞 destroys its holder, returns the equipment to the
+// hand and gains an operator; normal 博士投影 destroys itself, which splices holder.items), and a live walk skipped the
+// next item or ran it with a holder that was gone. Pieces gained or equipped during the walk wait for the next dispatch.
 // Dispatch order per player: global → band → bonds → garrisons (board reading order,
 // then hand) → equipped items → effects (insertion order); onPrice runs the priced chess's own 特质 first (购买价格为N
 // sets the price the discounts and caps of bonds / strategies then act on — user playtest #5). Every call is
@@ -515,9 +515,10 @@ export function makeCtx(m, ps, source, hook, ev = null) {
       return m.dispatcher.triggerGarrisons(ps, l.piece, eventType, { asPiece: as ? as.piece : null, triggeredBy: source.key || null });
     },
     promote: (uid) => { const l = ps.find(uid); return l ? ps.promote(l.piece) : false; },
-    /** Replace a chess piece by another chess (keeps its tile when legal, keeps its equipment — `{ returnItems: true }`:
-     *  the equipment returns to the hand instead, as from a destroyed operator; PlayerState.transformChess). */
-    transform: (uid, chessId, opts = {}) => { const l = ps.find(uid); if (!l || l.piece.kind !== 'chess') return null; const p = ps.transformChess(l.piece, chessId, { returnItems: !!(opts && opts.returnItems) }); return p ? view(p) : null; },
+    /** 突变细胞's transformation: destroy a chess piece wherever it stands (its equipment returns to the hand first), then
+     *  gain `chessId` like any gained operator — hand, overflow temp, a completed merge as usual
+     *  (PlayerState.transformChess). Returns the gained piece's view (the elite after a merge) or null. */
+    transform: (uid, chessId) => { const l = ps.find(uid); if (!l || l.piece.kind !== 'chess') return null; const p = ps.transformChess(l.piece, chessId); return p ? view(p) : null; },
     /** Normal item piece → its golden version in place. */
     upgradeItem: (uid) => { const l = ps.find(uid); return l && l.piece.kind === 'item' ? ps.upgradeItem(l.piece) : false; },
     /** Attach an owned hand/temp item to an owned chess without equip effects (copies, restores). */