feedback6: merge R21B — 联防 plays on the round's battlefield again, its terrain, crates, water, devices and runes as in 0.1.4 (the owner's report 「联防阶段地形全消失了」 and knowledge of the official mode, GitHub #244's tournament video; 0.2.0's escaped level was the placeholder road every wave-template level carries); the 联防 battle input is byte-identical to 0.1.4's in 20 cases; 乌尔比安's comment keeps both streams' sentences; golden as R21B's commit (unite-1 / unite-2 back to their stages, coop2-NORMAL-3, coop2-HARD-4, coop3-ABYSS-5, coop4-ABYSS-7, coop2-NORMAL-8-serverrun, coop2-NORMAL-14-standins), the merged tree differs from the branch only in R21A's boss pair fields

docs/history/0.2.0.md

@@ -419,6 +419,8 @@ machine-translated with the official terms, marked as such (§25.23).
   false`) carry the 联防 battle in both combat modes; the client draws that map and restores the board after. No water,
   crates, devices or terrain in 联防; the BGM (PR #110) is unchanged. [ASSUMED]: the records' names 联防阵地（1名玩家） /
   （2名玩家）. Golden: unite-1, unite-2 and the co-op matches. Tests: `test/match/feedback5-unite-map.test.js`.
+- **Withdrawn in 0.2.1**, see §26 — 联防 plays on the round's battlefield again (the owner's decision of 2026-10-07,
+  「官服保留地形」: the escaped levels' map is the placeholder road every wave template level carries).
 
 #### 25.6.5 伺夜's 狼群 has the official 战术点形态; S1 acts by the pack's state (PRTS 备注; the owner's decision of 2026-10-05) — `content/tokens.js wolfPack / installWolfTacticalPoint / wolfReturnNow`, `kits/ops/chess_char_3_19-vigil.js`