feedback7 R22-FIELDS: the path tie-break never wades into more 深水区 than the official route — on 战场#08(下半) the patrolling 铳 / 卢西恩 take the official upper road from (3,9) to (2,3) again (GitHub #375); golden: boss-boss_2-pair, coop2-ABYSS-10-boosted

GitHub #375 (FrogThai): 「水图boss会从下面这条路往蓝门走，实际应该从上路走」. The walking leaders of 战场#08(下半) 涨潮控制
(act2autochess_m04) are 铳 (level_act1autochess_h07_02 route 6; the Hidden Core 铳 on act1autochess_h08_02's patrol
routes) and 卢西恩 (act2autochess_h07_05 route 8): PATROL_MOVE (3,9) → (2,3) → (5,9). Measured (notes repro-375.mjs):
ours 「3,9 2,9 2,6 4,6 4,4 2,4 2,3」 — the lower road through the 深水区 (3,6) / (4,6) — against the official SPFA
「3,9 5,9 5,4 2,4 2,3」 along row 5 with one 深水区 (5,6); the mirrored (3,11) → (2,17) split the same way.
Cause: grid.js _buildField takes the blockable-ground preference pointer (user playtest #2) when its route crosses
strictly fewer non-blockable tiles; 深水区 is non-blockable itself (no deployment), so the lower road counted 2 against
the upper road's 3 (two floor tiles and one water tile) and won. Official pathfinding is the plain 4-neighbour SPFA
(research 08 §3.1). Now the preference pointer is taken only when its route also crosses no more 深水区 than the official
pointer's (a per-tile `deep` count beside `cost`, start excluded). Rule from the Grok triage (scratch-i1b/375.patch),
re-implemented with a precomputed Grid.deepWater mask (terrain 'deepsea': tile_deepsea and tile_deepwater).

Scope (notes dump-fields.mjs / check-official.mjs, every stage × normal / 联防 / boss rect × every walkable
destination): 48 fields change, only on the two water maps (act2 m04 boss field; the inactive act1 m05), 149 pointers,
every one back to the official pointer. The 21 accepted DEVIATIONS (战场#01 / #02 floor, #07, the inactive #05's 7
water-avoiding routes) are unchanged, as are all 154 audited gate routes and data/stages.json's groundPaths
(tools/build-data.mjs --offline into a scratch dir: every data file identical). Other boss-field preference routes of
m04 that cross fewer 深水区 than the official one stay.

Tests: test/sim/pathing-official.test.js — two new #375 tests (the four patrol legs equal the pure official waypoints;
in a real battle the 铳 climbs to row 5 and steps on the 深水区 (5,6) only), both failing on the parent;
test/sim/pathing-crosscheck.test.js — the independent reference port gets the same 深水区 rule (it flagged both the
patrol leg and a random-crate normal-field route of act2 m04 until then); test/sim/pathing-blockable.test.js — the WALK-leg
audit compares with the equal-length routes that cross no more 深水区 than ours (the 14 accepted arena exceptions
unchanged). Grid-related suites 777/777.

Golden:
- fields boss-boss_2-pair (铳 pair on act2autochess_m04, act1autochess_h07_02): the two 铳 patrol the upper roads;
  leader left 5311560 → 5301010, p1 damage up / p2 down, deaths 0 / 2 → 1 / 3; still 8 / 8 kills.
- matches coop2-ABYSS-10-boosted (act2 m04; Final Assault 卢西恩, Hidden Core 铳): still cleared, team LP 800 → 615. The
  bots' operators stand on the lower rows (the same tiles as before); with the leaders on the upper road the Final
  Assault lasts 335 game s instead of 247 and the Hidden Core 638 instead of 190, both past the 150 real-second mark:
  the overtime drain takes 17 + 168 LP (none before), no leak.

docs/SIM.md

@@ -215,7 +215,9 @@ WALK legs pathfind on the stage grid inside the rect with the official flow fiel
 destination, crates cost 1000, then Bresenham line-of-sight smoothing — research 08 §3.4). The official route stays
 unless 0.1.0's road-over-floor preference route (the fewest non-blockable tiles among equal-length chains, a line of
 sight that never covers floor — diagonal-step corners included — its grid route does not walk; user playtest #2 item 2)
-crosses strictly fewer non-blockable tiles (floor / gate lanes); "crosses" = passes through the tile's interior, a
+crosses strictly fewer non-blockable tiles (floor / gate lanes) and no more 深水区 (GitHub #375: on 战场#08(下半) the
+patrolling 铳 / 卢西恩 waded through two water tiles to dodge one floor tile; the official upper road crosses one);
+"crosses" = passes through the tile's interior, a
 corner touch does not count (`grid.js` `segmentTiles`; community report D5 after 0.1.0: 战场#04's lower-gate enemies cut
 diagonally from row 9 into row 10 as officially), and on equal counts the official route stays.
 test/sim/pathing-official.test.js lists the 21 of 154 stage routes that still differ from the official ones (战场#01's