Credibility pass: comments say what the code can't, and the seams are gone

Engine: pit-rim exits live in one helper (pitRimExits) shared by the
resolver and the automaton; chargeReach names the six-stride cap; dust
sight is inDust + dustAtEnd; PushPending is exported once; the force-field
counter builds its events in one list; drawUnderSlowDeath says what it
draws under. Test groups are named for the rule they pin, not the
revision that introduced it.

Client: one smoothstep; one edgeScar per battle-scarred edge; one
board-zone rule (which also seats the caption strip on phones); the
compass names live in SIDE_NAMES; net.flash() is the one toast; MediaQuery
replaces two hand-rolled matchMedia listeners; sprites carry their sizes
as plain numbers and their CSS in one rule each; canvas helpers are
formatted like the rest of the tree. Comments that told how a cel or a
fallback used to look now say what it draws. The actions-over notice no
longer blames a pickup when slime ended the turn.

Server and ops: dataRoot() is the one data directory; headlineOf builds
its deeds without a cast; the rollup and skills read the same way the
code behaves.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Jm2auWk6RP71CjaAb4FMoG

packages/engine/src/board.ts

@@ -253,6 +253,24 @@ export function stepTarget(
   return { kind: "blocked", by: "wall" };
 }
 
+/** The sides a walker may leave a pit by, having entered it heading
+ * `entry`: the neighbouring squares that offer footing, and the warp
+ * mouths on the rim, the way back excluded. `filled` names the squares
+ * nothing can land on. */
+export function pitRimExits(
+  board: AssembledBoard, pit: Cell, entry: Side, filled: (c: Cell) => boolean,
+): { floor: Side[]; mouths: Side[] } {
+  const floor: Side[] = [];
+  const mouths: Side[] = [];
+  for (const d of SIDES) {
+    if (d === opposite(entry)) continue;
+    const t = stepTarget(board, pit, d);
+    if (t.kind === "blocked" || filled(t.to)) continue;
+    (t.kind === "step" ? floor : mouths).push(d);
+  }
+  return { floor, mouths };
+}
+
 /**
  * Line of sight from the center of `from` to the center of `to`, blocked by
  * wall/door/firewall edges the segment crosses and by any `blockedCells`