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.

test/sim/pathing-crosscheck.test.js

@@ -5,8 +5,9 @@
 // preference field = 0.1.0's — equal-length ties to the chain with the fewest non-blockable tiles, a line of sight that
 // covers non-blockable tiles, diagonal-step corners included, only on the own raw chain — whose pointer replaces the
 // official one where its route crosses fewer non-blockable tiles, or as few while only skipping the official waypoint
-// (on the straight line to it, leading there); "crosses" = positive-length intersection with the tile, found here by
-// clipping the segment against each tile, independently of grid.js crossTiles):
+// (on the straight line to it, leading there), and no more 深水区 than the official route (GitHub #375); "crosses" =
+// positive-length intersection with the tile, found here by clipping the segment against each tile, independently of
+// grid.js crossTiles):
 //   * the 8 active stages with their match-start devices: the smoothed chain from EVERY walkable tile of the normal,
 //     联防 and boss rects to every goal equals the full-map reference one (the sim's rect limit changes nothing);
 //   * 400 random crate / block layouts: identical chains to the same algorithm limited to the rect;
@@ -56,6 +57,8 @@ function official(sid, { crates: extraCrates = [], blocks: extraBlocks = [], rec
     if (t.tileKey === 'tile_deepsea') return true;
     return !(t.heightType === 'LOWLAND' && (t.buildableType === 'ALL' || t.buildableType === 'MELEE'));
   };
+  /** 深水区 — the preference may not cross more of it than the official route (#375) */
+  const deep = (r, c) => ['tile_deepsea', 'tile_deepwater'].includes(tile(r, c).tileKey);
   const bres = ([r0, c0], [r1, c1], clear) => {
     const dr = Math.abs(r1 - r0), dc = Math.abs(c1 - c0), sr = r1 > r0 ? 1 : -1, sc = c1 > c0 ? 1 : -1;
     let err = dc - dr, r = r0, c = c0;
@@ -140,12 +143,15 @@ function official(sid, { crates: extraCrates = [], blocks: extraBlocks = [], rec
     const off = spfa(false);
     const dist = off.dist;
     const segNb = (a, b) => through(a, b).filter(([y, x]) => !(y === a[0] && x === a[1]) && nb(y, x)).length;
+    const segWet = (a, b) => through(a, b).filter(([y, x]) => !(y === a[0] && x === a[1]) && deep(y, x)).length;
     let nxt = smooth(off, false);
     if (prefer) {
       // per tile in increasing distance: the preference pointer when its route crosses fewer non-blockable tiles (or as
       // few while it only skips the official waypoint: o strictly inside the segment a → p, and o's chosen pointer is p)
+      // and no more 深水区 than the official pointer's route
       const nxtP = smooth(spfa(true), true);
       const cost = new Map([[D, 0]]);
+      const wet = new Map([[D, 0]]);
       const chosen = new Map();
       const skips = (a, o, p) => {
         const t = through(a, p);
@@ -155,9 +161,11 @@ function official(sid, { crates: extraCrates = [], blocks: extraBlocks = [], rec
         if (k === D) continue;
         const a = unkey(k), o = nxt.get(k), p = nxtP.get(k);
         const co = segNb(a, o) + cost.get(key(o)), cp = segNb(a, p) + cost.get(key(p));
-        const useP = cp < co || (cp === co && key(o) !== key(p) && key(chosen.get(key(o)) ?? []) === key(p) && skips(a, o, p));
+        const wo = segWet(a, o) + wet.get(key(o)), wp = segWet(a, p) + wet.get(key(p));
+        const useP = wp <= wo && (cp < co || (cp === co && key(o) !== key(p) && key(chosen.get(key(o)) ?? []) === key(p) && skips(a, o, p)));
         chosen.set(k, useP ? p : o);
         cost.set(k, useP ? cp : co);
+        wet.set(k, useP ? wp : wo);
       }
       nxt = chosen;
     }