feedback1 cell: docs for the 突变细胞 bench rule (DESIGN §21.1 / §20.11 / §21.20, META, PLAYING, DATA, research, CHANGELOG)

- DESIGN §21.1 states the corrected rule with its evidence: bilibili BV1vzyVBuEN9 (上半, about 8:24) and
  BV1Qkw1zMEoR (下半, about 7:25) show the carrier's tile empty at the next prep, one more deployment left
  and the new operator on the bench; the PRTS 备注 is a destroy followed by a gain; PRTS 帮助 sends what a
  player gains to the 手牌区; the closed PR #2 said the same (its merge path not adopted). The WA
  keep-the-tile rule and the carrier-tile merge exception are withdrawn; the bench carrier and the
  hand-and-temp-full case stay [ASSUMED].
- §20.11 / §20.9 no longer count a transformed carrier's tile; §21.20 lists the rule as official;
  §21.25 credits PR #2's bench rule; §6.2 and §6.6 follow; the §21 intro maps it.
- META (bot, ctx.transform, built-ins, merge, notes), PLAYING, DATA (items.json note), research 04
  (addendum 2, implFormula, open question 6) and research 01 row 7 follow.
- One CHANGELOG 0.1.1 line (PR #2 指出).
- docs-consistency pins the docs against the code (no fromKey / returnItems left, the gain through
  acquireChess).

docs/research/01-core-rules.md

@@ -842,7 +842,7 @@ Local copies are in `scratchpad/gd/extra/critic/` (`bw_盟约.txt`, `bw_sweep.tx
 | new | – | At **combat start, all unfrozen shop contents are cleared** ("进入作战期后，栏上若未处于冻结状态则清空全部物资"). | VERIFIED |
 | 4.2 / 8 | bench 10 + temp area | **Hand (手牌区/整备区) = 10 regular + 5 temporary slots**, shared by operators, **items** and hand-deployable **summons**. Several summons of one owner stack into 1 slot; summons of different owners don't stack.<br>When the regular hand is full, every action that would add a card is refused: buy, and withdraw from the board. Exception: a purchase that completes a 3-merge nets −1 card, so allow it.<br>Passive gains (merge result, band/trait/item grants, items returned by promotion) overflow into the temp slots. **While temp is non-empty the player cannot start combat.** Temp is wiped when the next phase starts.<br>A board↔hand swap is allowed even with a full hand. Cards fill hand slots **right→left**. | VERIFIED |
 | 5.2 | – | **Items cannot be sold** ("多余的装备无法进行出售，可以销毁"). They can only be destroyed for 0 funds. Operators sell for 1 from board or hand. | VERIFIED |
-| 7 | promotion reward [COMM] | Confirmed (PRTS 帮助, BWIKI, official intro). On acquiring the 3rd copy:<br>1. The 3rd copy is not created, and the 2 owned copies are destroyed wherever they are.<br>2. **1 elite goes to the hand — or, when a consumed copy was deployed, to that copy's board position** (PRTS 帮助 "发送1名【精锐】状态的该干员至手牌区（若消耗已部署至作战区的干员，则发送至作战区对应位置）"; the user confirmed it first-hand after playtest #6 — this row used to read "not to a board tile", a misreading of the same sentence). Their equipment returns to the hand ("干员晋级后已配发装备会回收至整备区，需要重新配置"). [ASSUMED] where the text is silent: with two or three deployed copies the elite takes the tile of the one that deploys first (top→bottom, then left→right — the official deploy order) with its facing; a deployed operator transformed into the completing copy (突变细胞) counts as deployed; the copies' summons leave and the elite's own summon card joins the hand (§战斗部署 "如果部署的干员拥有可手动部署的附属召唤物，则该召唤物会立刻加入手牌区"); the deploy count never grows.<br>3. The shop then temporarily shows **3 operators of tier min(shopLevel+1, 6) at price 0**. The official intro shows "II 0 ×3" after a tier-I merge at L1 and "III 0 ×3" at L2.<br>4. The player takes **1**. The offer cannot be refreshed or frozen and expires at round end. | VERIFIED (elite to the copy's board position: PRTS + the user); the tile among several deployed copies ASSUMED |
+| 7 | promotion reward [COMM] | Confirmed (PRTS 帮助, BWIKI, official intro). On acquiring the 3rd copy:<br>1. The 3rd copy is not created, and the 2 owned copies are destroyed wherever they are.<br>2. **1 elite goes to the hand — or, when a consumed copy was deployed, to that copy's board position** (PRTS 帮助 "发送1名【精锐】状态的该干员至手牌区（若消耗已部署至作战区的干员，则发送至作战区对应位置）"; the user confirmed it first-hand after playtest #6 — this row used to read "not to a board tile", a misreading of the same sentence). Their equipment returns to the hand ("干员晋级后已配发装备会回收至整备区，需要重新配置"). [ASSUMED] where the text is silent: with two or three deployed copies the elite takes the tile of the one that deploys first (top→bottom, then left→right — the official deploy order) with its facing; the copies' summons leave and the elite's own summon card joins the hand (§战斗部署 "如果部署的干员拥有可手动部署的附属召唤物，则该召唤物会立刻加入手牌区"); the deploy count never grows. A 突变细胞 carrier is destroyed before its new operator is gained (official footage, DESIGN §21.1), so a merge that operator completes never uses the carrier's tile.<br>3. The shop then temporarily shows **3 operators of tier min(shopLevel+1, 6) at price 0**. The official intro shows "II 0 ×3" after a tier-I merge at L1 and "III 0 ×3" at L2.<br>4. The player takes **1**. The offer cannot be refreshed or frozen and expires at round end. | VERIFIED (elite to the copy's board position: PRTS + the user); the tile among several deployed copies ASSUMED |
 | 2 | BAND_CHECK "3 random + reroll" [ASSUMED] | **All unlocked bands are shown.** In co-op, players pick **one at a time in a random order** shown on the left ("以随机顺序进行策略轮选"). Each co-op player may **skip once**. The step lasts 50 s; on timeout the band is 华法琳. **Duplicates are allowed:** the official illustration shows 2 teammates' picks still un-greyed in the grid. [ASSUMED] 12 s per turn inside the 50 s step. | VERIFIED except the per-turn timer |
 | 2 | banned bonds "1 core + 1 add-on" [ASSUMED] | Replaced by the verified rule in **A2**. | VERIFIED |
 | 1, 12 | one ×0.7/×0.8 multiplier per mode; `aceffect_enemy_*` mapping [ASSUMED] | Replaced by the **per-round table in A3**. | VERIFIED (PRTS, user-sourced) |