Tests: test/sim/feedback5-raid-own-board.test.js — the pair field (the right player's member onto the left telin's board tile (2,3), the left player's onto the mirrored right (2,17), the hand rows closed) and the two-helper 联防 (each helper onto the other's half; 乌尔比安 beside a teammate stays on his own) fail on the parent; the solo boss field's hand rows and the lone helper unchanged.
Docs: docs/history/0.2.1.md (new, §26; §26.1 cites the owner's decision and PRTS 卫戍协议/帮助 §联防阶段), the DESIGN index row and versions line, a pointer from §25.18.1, docs/SIM.md (onFieldBoard; onOwnBoard now 乌尔比安's only).
Cause: raidTile took any standable tile of the battle rect; BOSS_RECT holds rows 0-1 (tile_achand, buildable high
ground) and UNITE_RECT both halves of the 联防 map. Battle.onOwnBoard(ps, r, c) maps the board region (rows 9-12,
cols 2-10) onto the field as mapTile maps the pieces; raidTile takes only those tiles.
Golden: 8 scenarios, each with members that landed on the partner's half on the parent (checked instrumented):
fields boss-boss_2/3/4/5/6-pair, hidden-boss_8/10-pair; matches coop2-ABYSS-10-boosted (ai_0 on the right half).
Tests: test/sim/feedback5-raid-own-board.test.js (4, fail on the parent). Docs: DESIGN §25.18.1, docs/SIM.md.