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  keep-the-tile rule and the carrier-tile merge exception are withdrawn; the bench carrier and the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/04-items.json

@@ -5493,7 +5493,7 @@
    "talentNotes": [
     "本装备不会合并为进阶品质"
    ],
-   "implFormula": "After the battle ends: replace the carrier with a random operator one tier higher (max tier 6); item consumed [ASSUMED]. Keeps elite status? [ASSUMED: result is NORMAL quality; other equipped item returns to hand]. Never merges.",
+   "implFormula": "After the battle ends: the carrier is destroyed wherever it stands (a board tile is freed); its equipment, the cell included, returns to the hand first (the cell is not consumed); then a random NORMAL operator one tier higher (max tier 6; an elite carrier too) is gained like any gained operator, into the 整备区 (overflow temp), never onto the carrier's tile. Never merges. [Corrected after 0.1.0 — the first reading was 'item consumed [ASSUMED]': PRTS 下半 记录 备注 '生效时，原干员销毁，获得一名高一阶的随机初始干员（最高六阶）'; official footage bilibili BV1vzyVBuEN9 / BV1Qkw1zMEoR (the tile empty, the operator on the bench; PR #2); see the 04-items.md addenda.]",
    "normal": {
     "chessId": "chess_item_5_08_e_a",
     "isGolden": false,