feat(rendering): contain incremental render scene

Pin Arch behind acdream-owned identities, deltas, queries, generation gates, and memory diagnostics. The new five-archetype store is unbound and non-drawing so static publication can be shadowed without changing production behavior.

Co-authored-by: Erik Nilsson <erikn@users.noreply.github.com>

docs/plans/2026-07-24-modern-runtime-slices-f-g-render-scene.md

@@ -18,8 +18,9 @@ retail-faithful gameplay
 |---|---|---|
 | F0a — partition-input referee | complete | Diagnostic-only `CurrentRenderSceneOracle`; no production draw decision changed. |
 | F0b — survivor/dispatcher/selection referee | complete | Exact PView routes, dispatcher candidates and final group payloads, material/alpha/clip/light/selection fields, and accepted picking parts. Release gate: 3,690 App tests / 3 skips and 8,174 complete-solution tests / 5 skips. |
-| F1 — scene types and contained adapter | active | No render-scene storage or shadow projection exists yet. |
-| F2–F5 | pending | Delta publication and continuous shadow comparison have not started. |
+| F1 — scene types and contained adapter | complete | `Arch 2.1.0` is pinned in App only behind acdream contracts. Five narrow archetypes, generation/incarnation/sequence gates, borrowed-query invalidation, memory accounting, deterministic digesting, and update-thread enforcement pass 11 focused tests. Release gate: 3,701 App tests / 3 skips and 8,185 complete-solution tests / 5 skips. |
+| F2 — static projection journal | active | Static publication/retirement owners do not emit render deltas yet. |
+| F3–F5 | pending | Live/equipped publication, dynamic indices, and continuous shadow comparison have not started. |
 | G0–G5 | pending | No production consumer has switched. |
 
 The exact pre-F/G runtime rollback anchor remains `e7d9d6fa`. F0 is
@@ -314,6 +315,17 @@ performance regression with comparison disabled.
 
 **Commit gate:** the scene is unbound and non-drawing; full suite green.
 
+**Landed evidence:** the package/API/license decision is recorded in
+`docs/research/2026-07-24-arch-render-scene-dependency.md`. Production
+composition does not construct `ArchRenderScene`; F1 therefore changes no
+runtime path. Source/reflection architecture tests confine all Arch types and
+primitive-ID extraction to `AcDream.App/Rendering/Scene/Arch`. Pure App tests
+cover every structural/channel operation, generation replacement, stale
+incarnation and sequence rejection, borrowed-query invalidation, deterministic
+digest order, retained-memory accounting, and cross-thread mutation rejection.
+The Release gate is 3,701 App tests / 3 skips and 8,185 complete-solution tests
+/ 5 skips.
+
 ### F2 — Static projection journal
 
 1. Append Register deltas from the existing final landblock spatial publication

docs/research/2026-07-24-arch-render-scene-dependency.md

@@ -0,0 +1,77 @@
+# Arch render-scene dependency decision
+
+**Date:** 2026-07-24
+
+**Scope:** Modern Runtime Slice F1 only
+
+## Decision
+
+Pin `Arch` version `2.1.0` directly in `AcDream.App`. Do not reference it from
+Core, UI abstractions, plugins, or any other production project. Do not use
+Arch systems, command buffers, parallel queries, jobs, events, source
+generators, persistence, relationships, or extension packages.
+
+The only allowed Arch namespace is:
+
+```text
+src/AcDream.App/Rendering/Scene/Arch/
+```
+
+Everything outside that folder uses acdream-owned `IRenderScene`, wrapper
+identities, packed component values, deltas, borrowed queries, digests, and
+memory-accounting values. Arch entities and primitive wrapper values cannot
+cross that boundary.
+
+## Verification
+
+- Official package: [NuGet `Arch 2.1.0`](https://www.nuget.org/packages/Arch/2.1.0)
+- Official source/tag:
+  [genaray/Arch `v2.1.0`](https://github.com/genaray/Arch/tree/v2.1.0)
+- License:
+  [Apache License 2.0](https://github.com/genaray/Arch/blob/v2.1.0/LICENSE.MD)
+- Selected source tag commit:
+  `04d52e7268eb6f376ca4841a0c204334120c5e9d`
+
+The selected package supplies .NET 6 and .NET Standard 2.1 assets, both
+compatible with acdream's .NET 10 App target. The v2.1.0 source was inspected
+for the exact API used by the adapter:
+
+- `World.Create`
+- generic `World.Create<T...>`
+- `World.Set<T>` / `World.Get<T>`
+- `World.Destroy(Entity)` / `World.Destroy(World)`
+- `World.Size`, `World.Capacity`, and `World.Archetypes`
+- archetype chunk count and chunk-size accounting
+
+The resolved dependency graph was captured with
+`dotnet list package --include-transitive`. It resolves:
+
+```text
+Arch                         2.1.0
+Arch.LowLevel                1.1.5
+Collections.Pooled           2.0.0-preview.27
+CommunityToolkit.HighPerformance 8.4.0
+Microsoft.Extensions.ObjectPool  7.0.0
+ZeroAllocJobScheduler        1.1.2
+```
+
+No package in the resolved App graph was reported vulnerable by NuGet's
+`--vulnerable --include-transitive` audit on 2026-07-24. The transitive job
+scheduler is not initialized or called by acdream; Slice F uses only
+single-threaded structural operations and direct component access on the
+existing update thread.
+
+## Containment proof
+
+`RenderSceneArchitectureTests` enforces all of the following:
+
+1. `Arch` is a direct package reference in `AcDream.App` only.
+2. Arch namespaces occur only in the contained adapter folder.
+3. Reflection finds no Arch field, property, parameter, or return type outside
+   that namespace.
+4. Raw wrapper identity extraction occurs only in the adapter (apart from the
+   private contract declarations themselves).
+
+This is storage selection, not simulation architecture. `LiveEntityRuntime`,
+`GpuWorldState`, gameplay identities, retail PView, GL ownership, and all
+behavioral owners remain authoritative and unchanged.