# Slice I6 — flat production collision cutover

## Result

Commit `068a06518dd710ca5e7f166754cbb7789ca1ed0f` makes the immutable
prepared collision representation authoritative for gameplay. The parsed DAT
graph remains temporarily resident only as the automated differential referee.

Production now:

- creates its `PhysicsDataCache` through the explicit production factory;
- fails publication when a required prepared GfxObj, Setup, CellStruct, or
  EnvCell topology record is genuinely absent;
- accepts idempotent publication when that flat asset is already resident;
- returns flat results even when the graph referee disagrees;
- uses flat containment for the unified cell graph;
- uses flat polygon tables for nearest indoor floor lookup;
- derives live/static BSP shape bounds and camera diagnostics from flat data.

Graph-only cache construction remains an explicit test/tooling oracle seam
until the post-acceptance deletion commit.

## Exact rollback

```text
git revert 068a06518dd710ca5e7f166754cbb7789ca1ed0f
```

Do not revert the I3 package schema, I4 traversal, or I5 dual-publication
commits.

## Automated conformance

- Release build: pass.
- Complete Release solution: 8,402 passed / 5 skipped.
- Warm flat traversal: 0 B.
- Reused resolver scratch across player, remote, projectile, camera, and
  grounded mover families: 0 B/resolve.
- Retained render hot-path allocation fixtures: pass.
- Flat-authoritative mismatch fixture proves the graph cannot change gameplay.
- Production publication fixtures prove missing prepared data fails and an
  already-resident prepared asset remains idempotent.

## Connected strict-publication/referee gate

Evidence:
`logs/connected-dense-town-20260725-165758.report.json`.

- PASS with graceful authoritative logout and `WM_CLOSE`.
- Dense Arwic: 15,530 entities / 111 animated.
- Collision referee: 46,309 queries, 46,309 exact matches.
- Mismatches: 0.
- Referee faults: 0.
- Mismatch artifacts: 0.
- Stable cell residency: 292 graph / 292 flat during the referee window.

The first strict attempt correctly exposed an idempotency-contract defect:
`LiveCollisionAssetPublisher` passed `null` after finding the prepared asset
already resident, and the guard interpreted that as absent. The root fix makes
the cache distinguish “already published” from “not provided”; strict missing
package data still fails.

## Production-like performance check

The normal connected gate intentionally enables the complete current-path
render oracle and allocates about 10.8 MiB/frame in dense Arwic. It is a
correctness observer, not a production performance measurement.

A separate Release run used the same dense-Arwic arrival and six-second camera
turn with:

- uncapped rendering;
- no lifecycle artifact directory;
- no current-path render oracle;
- no collision referee;
- no runtime counter attachment.

Stable result:

- about 190–200 FPS;
- CPU p50 about 5.0 ms;
- CPU p95 about 5.9–7.3 ms;
- GPU p95 about 2.1 ms;
- update p95 about 1.4–1.8 ms;
- roughly 8% total-machine CPU;
- working set about 1.12 GiB;
- private bytes about 1.41 GiB;
- warm allocation about 84.6 KiB/frame in the dense scene.

The parsed graph is still resident in those memory figures. I6 graph removal
must reduce that footprint and prove stable production graph counts are zero.

## Acceptance boundary

The automated cutover gate is complete. Before deleting the referee and parsed
graph, the user must verify outdoor/indoor movement, doors, ramps/stairs,
jump/fall, camera-wall collision, object interaction, combat/projectiles, and
portal/reconnect behavior on the cutover commit.