docs: the trap hunt for section 15, before and after

286 distinct tiles become 489 over twenty brain minutes from the rung-9
checkpoint, the median flagged window holds 55 tiles instead of 16, GO FRONTIER
runs 64 walks worth up to twelve net tiles instead of four worth one, and one
walk spends its cap where six did.

The cost is named rather than buried: flagged windows go 61 to 70 and windows
under four tiles 5 to 14, and every one of those is a window spent inside a
battle -- a fly that covers more ground walks into more grass, 48,756 battle
frames becoming 50,413 with the longest battle 9,549 frames becoming 13,411.
This is the first measurement in that file where more ground and fewer flags do
not both hold, and it is stated as such.

docs/design/macros.md

@@ -1168,5 +1168,11 @@ before the map**, which is what the per-serve check above is for.
   `GO FRONTIER` in the forest planned to ground outside the window and walked there in 215 frames
   (615 of its frontier tiles are outside the window); every way out of the forest is one plan away,
   27 to 149 steps, with no guessed tile in any of them.
-- **The trap hunt**, twenty brain minutes from the rung-9 checkpoint, before and after, is in
-  `infra/docs/macros-traps.md`.
+- **The trap hunt**, twenty brain minutes from the rung-9 checkpoint, against `main` at v0.4.2:
+  **286 distinct (map, tile) become 489**, the median flagged window holds 55 tiles instead of 16,
+  `GO FRONTIER` runs 64 walks worth up to twelve net tiles instead of four worth one, and one walk
+  spends its cap where six did. It costs battle: flagged windows go 61 to 70 and windows under four
+  tiles 5 to 14, every one of them a window spent inside a battle, because a fly that covers more
+  ground walks into more grass. `infra/docs/macros-traps.md` has both runs whole and says so at
+  length; this is the one measurement in this file where more ground and fewer flags do not both
+  hold.

infra/docs/macros-traps.md

@@ -1359,3 +1359,71 @@ Four things about it that are not improvements, recorded rather than buried.
 - `infra/tests/lint.sh`: all checks passed, de-PII guard included.
 - `--print-compatibility`: byte-identical to v0.4.1, 648 bytes, decoder / reward catalog / adapter
   version / roles untouched.
+
+## 2026-09-22, section 15: the walkable window becomes the whole map
+
+The operator: "the frontier and warp macros need to be map aware: A* over walkable tiles."
+`docs/design/macros.md` section 15 is the contract, `docs/design/macros-wram.md` section 9 the
+bytes, and this is the measurement. Nothing about the *choice* moves: the scene deals the same
+buttons and what changed is what a chosen walk knows about the ground.
+
+**Row 35 has no source any more.** That row — "the screen-buffer tile read disagrees with itself on
+a map smaller than the screen", worked around by taking a counter's reach from the map id — was a
+fact about reading tiles out of a view that cannot centre on an 8x8 map. The grid reads the map's
+own block data, so it answers the same way from every tile of every map. The counter rule is left
+exactly as it is: this branch changes the ground, not the amenity, and a workaround that is no
+longer needed is not the same thing as one that was wrong.
+
+### The trap hunt, before and after
+
+20 brain minutes, the hunt's own seed, 4 sweep threads, the same connectome, the same cartridge and
+the same rung-9 checkpoint in both runs. "Before" is `main` at v0.4.2, which is the branch's own
+merge base, so the two rows differ by this work and nothing else:
+
+```sh
+FLY_ROM=".../Pokemon Red (U) [S][BF].gb" FLY_MACRO_BRAIN=data/fafb-v783 \
+  FLY_TRAP_CHECKPOINT=.local/checkpoints/release-rank9-20260922T0254.checkpoint \
+  FLY_TRAP_MINUTES=20 FLY_TRAP_MODE=macros cargo run --release -p flysim --example trap_hunt
+```
+
+| measure | before (`main`, v0.4.2) | after (this branch) |
+| --- | ---: | ---: |
+| distinct (map, tile) over 20 brain minutes | 286 | **489** |
+| median distinct tiles in a flagged window | 16 | **55** |
+| most tiles in any one window | 94 | **180** |
+| macros started | 830 | 912 |
+| done / blocked / timeout / refused | 726 / 97 / 6 / 0 | 820 / 90 / **1** / 8 |
+| windows flagged | 61 of 73 | 70 of 73 |
+| windows under 4 distinct tiles | 5 | 14 |
+| frames in a battle (longest run) | 48,756 (9,549) | 50,413 (13,411) |
+| frames in the overworld | 22,149 | 18,972 |
+| `GO FRONTIER` done / timeout / mean net / max net tiles | 4 / 1 / 0.5 / 1 | **64** / 0 / 1.6 / **12** |
+| `GO WARP` done / timeout / mean frames / max net | 14 / 2 / 403 / 30 | 4 / **0** / 751 / 26 |
+| `GO ROUTE` done / timeout / mean frames / max net | 9 / 2 / 483 / 22 | 11 / 1 / 410 / 8 |
+| `GO OBJECTIVE` done / timeout / max net | 3 / 1 / 8 | 5 / **0** / **42** |
+| wall seconds on the development box | 1,390 | 932 |
+
+**The ground is the measure and the ground moved.** 286 distinct tiles became 489; the median
+flagged window holds 55 of them instead of 16 and the widest holds 180 instead of 94. `GO FRONTIER`
+went from four walks worth a net tile each to sixty-four worth up to twelve, `GO OBJECTIVE`'s best
+walk from eight net tiles to forty-two, and the only walk that spent its cap is one `GO ROUTE` that
+gained forty-two tiles while doing it. Nothing timed out that used to arrive.
+
+**The cost, named rather than buried: the flag count went the wrong way**, 61 windows to 70, and
+the windows holding fewer than four tiles went 5 to 14. Every one of those is a battle. The fly
+covers more ground, so it walks into more grass and more trainers: battle frames 48,756 to 50,413,
+the longest single battle 9,549 frames to 13,411, overworld frames 22,149 down to 18,972. A
+two-minute window spent inside one battle is a window with one tile in it, and the worst window of
+the after-run is 83 macros on one tile with **no repeated sequence at all** — which is a battle,
+not a loop. This file has recorded battle text as check 10's known false-positive shape since its
+first section, and the `NEXT` x12 to x14 runs that flag 43 of the 70 windows are exactly it.
+
+So the two halves of the usual reading disagree here for the first time, and this is the honest
+statement of it: **more ground, more battle, more flags.** What the flag counts cannot show and the
+tile counts can is that the fly is walking across maps instead of round the tile it is standing on.
+
+### Gates
+
+`cargo test --workspace`, `cargo clippy --all-targets` and `infra/tests/lint.sh` on the development
+box. `flysim --print-compatibility` is byte-identical across the change: 648 bytes,
+`0d9bfde7…707fa`, so the live checkpoint carries over.