Merge branch 'claude/hopeful-darwin-ae8b87' — Phase A.5 SHIP + Quality Preset system

Phase A.5 — Two-tier Streaming + Horizon LOD shipped.

Headline: 2.3 km terrain horizon (radius=4 near + 12 far) with off-thread
mesh build, fog blend at N₁, mipmaps + 16x AF, MSAA 4x + A2C foliage,
depth-write audit, BUDGET_OVER diag, Quality Preset system (Low/Medium/
High/Ultra) with env-var overrides + F11 mid-session re-apply.

~999 tests pass, 8 pre-existing physics/input failures unchanged.

Two structural-to-A.5 bug fixes shipped post-T26:
- Bug A (9217fd9): far-tier worker strips entities (T13/T16 had only
  wired the controller side; far-tier was loading full entity layers,
  ~71K entities instead of ~10K, 5x perf regression).
- Bug B (0ad8c99): WalkEntities scratch list reused across frames
  (was 480 KB / frame allocation).

Tier 1 entity-classification cache attempted as polish (3639a6f),
reverted (9b49009) — broke animation by caching mutable per-frame
state. Retry deferred to post-A.5 polish phase (ISSUE #53).

Deferred to post-A.5 polish:
- Tier 1 retry with animation-mutation audit (ISSUE #53)
- Lifestone missing visual (ISSUE #52)
- JobKind plumbing through BuildLandblockForStreaming (ISSUE #54)
- Tier 2 (static/dynamic split) + Tier 3 (GPU compute cull) —
  separate multi-week phases. Roadmap at
  docs/plans/2026-05-10-perf-tiers-2-3-roadmap.md.

SHIP commit: 9245db5.

docs/plans/2026-04-11-roadmap.md

@@ -1,6 +1,6 @@
 # acdream — strategic roadmap
 
-**Status:** Living document. Updated 2026-05-09 for Phase N.5b shipping (terrain on the modern rendering path via Path C — mirror WB's `TerrainRenderManager` pattern, consume `LandblockMesh.Build` for retail formula compliance; closes ISSUE #51). N.6 (perf polish) remains the in-flight phase.
+**Status:** Living document. Updated 2026-05-10 for Phase A.5 shipping (two-tier streaming N₁=4/N₂=12 + QualityPreset system + Bug A/B fixes; closes the two-tier streaming spec). Post-A.5 polish (Tier 1 retry + lifestone fix + JobKind plumbing) is now the in-flight work.
 **Purpose:** One source of truth for where the project is and where it's going. Every observed defect or missing feature has a named phase that owns it; when something looks wrong in-game, look here to find the phase that'll address it. Implementation details live in per-phase specs under `docs/superpowers/specs/`, not in this file.
 
 ---
@@ -31,6 +31,7 @@
 | A.1 | Streaming landblock loader — runtime-configurable visible window (default 5×5, `ACDREAM_STREAM_RADIUS`), camera-centered offline / player-centered live, hysteresis-based unloads, pending-spawn list for late CreateObject events | Live ✓ |
 | A.2 | Frustum culling — per-landblock AABB test (Gribb-Hartmann), terrain + static-mesh renderers skip culled landblocks, perf overlay in window title | Visual ✓ |
 | A.3 | Background net receive thread — dedicated daemon thread buffers UDP into Channel, render thread drains | Visual ✓ |
+| A.5 | Two-tier streaming + horizon LOD — N₁=4 (full detail, 81 LBs) + N₂=12 (terrain only, 544 LBs); fog blend at N₁; per-LB entity dispatcher walk tightened (Change #1 animated-walk fix + Change #2 cached AABB); single-worker off-thread mesh build; mipmaps + 16x anisotropic on TerrainAtlas; A2C with MSAA 4x on foliage; depth-write audit + lock-in test; **NEW T22.5: QualityPreset system** (Low/Medium/High/Ultra) with per-preset radii + MSAA + anisotropic + A2C + completions; env-var overrides per field; F11 mid-session re-apply. **Bug fixes post-T26 ship-prep**: (Bug A) far-tier worker now strips entities from far-tier loads — without this fix, far-tier LBs were loading their full entity layer (~71K entities) defeating the two-tier optimization; (Bug B) WalkEntities switched from per-frame fresh-list allocation to caller-provided scratch list (eliminated ~480 KB/frame GC pressure). **Deferred to post-A.5**: Tier 1 entity-classification cache (first attempt broke animation; revert + redo with animation-mutation audit), lifestone visual (missing in render), JobKind plumbing through BuildLandblockForStreaming (proper Bug A fix), Tier 2/3 perf optimizations (roadmap at docs/plans/2026-05-10-perf-tiers-2-3-roadmap.md). Plan archived at docs/superpowers/plans/2026-05-09-phase-a5-two-tier-streaming.md. | Live ✓ |
 | B.3 | Physics MVP resolver foundation — terrain contact, CellSurface prototype, streaming-populated collision inputs, and first `PhysicsEngine` resolver path. Not the complete retail collision system. | Tests ✓ |
 | B.2 | Player movement mode — Tab-toggled WASD ground walking, walk/run/idle animations, third-person chase camera, MoveToState + AutonomousPosition outbound, portal entry. Outdoor-only MVP. | Live ✓ |
 | D.1 | 2D ortho overlay + font rendering (StbTrueTypeSharp atlas + TextRenderer + DebugOverlay) | Visual ✓ |
@@ -82,7 +83,7 @@ Plus polish that doesn't get its own phase number:
 - **✓ SHIPPED — A.2 — Frustum culling.** Per-landblock AABB test (Gribb-Hartmann plane extraction + positive-vertex AABB test) in both `TerrainRenderer.Draw` and `StaticMeshRenderer.Draw`. Per-entity culling deferred. LOD deferred to Phase C. Performance overlay in window title shows FPS, frame time, visible/total landblock ratio, entity count, animated count. ~160fps uncapped at 5×5 radius.
 - **✓ SHIPPED — A.3 — Background net receive thread.** Dedicated daemon thread continuously pulls raw UDP datagrams from the kernel buffer into a `Channel<byte[]>`. Render thread's `Tick()` drains the channel. All decode, fragment assembly, ISAAC crypto, event dispatch, and ack-sending remain on the render thread — minimal change that prevents packet drops during frame stalls. Thread starts after `EnterWorld()` completes; `PumpOnce()` during handshake still reads the socket directly.
 - **A.4 — Async dat decoding.** Folded into the streaming worker — it's the worker's read path, not a separate subsystem. Called out here because regressions in dat caching could land on this surface.
-- **A.5 — Two-tier streaming + terrain horizon LOD.** Split `ACDREAM_STREAM_RADIUS` into two: `ACDREAM_TERRAIN_RADIUS` (large, 8-12 cells = 1.5-2.3km) for terrain mesh + `ACDREAM_ENTITY_RADIUS` (small, 2-3 cells, current default) for entities + scenery. Distant landblocks render terrain only — no NPCs, no procedural scenery, no static objects. Tune `SceneLightingUbo`'s `uFogParams` so the far edge fades into sky color (eliminates the hard streaming boundary visible at higher radii). Optional: terrain LOD via mesh decimation for very distant chunks (combine 2×2 landblocks into one decimated mesh; cribs from `references/WorldBuilder/Chorizite.OpenGLSDLBackend/Lib/TerrainRenderManager.cs`). Motivation: at radius=5 today, perf scales from ~810 fps → ~200-300 fps because everything stays full-detail; both retail and WorldBuilder render terrain way out and strip entities/scenery at distance. Enables WB-style horizon visibility. **Estimate: 3-5 days for the radius split + fog tuning; +1 week if terrain LOD is included.** Not yet brainstormed.
+- **✓ SHIPPED — A.5 — Two-tier streaming + horizon LOD.** Shipped 2026-05-10. See shipped table above for full description. Plan archived at `docs/superpowers/plans/2026-05-09-phase-a5-two-tier-streaming.md`.
 
 **Acceptance:**
 - Walk across 10+ landblocks in any direction, no crashes, no empty voids.
@@ -665,7 +666,7 @@ for our deletions/additions; merge upstream `master` periodically.
   manifest at higher radius. Spec acceptance criterion #5 was wrong;
   amended via `docs/plans/2026-05-09-phase-n5b-perf-baseline.md`. Plan
   archived at `docs/superpowers/plans/2026-05-09-phase-n5b-terrain-modern.md`.
-- **N.6 — Perf polish.** **Currently in flight.**
+- **N.6 — Perf polish.** **Planned (post-A.5 polish takes priority).**
   Builds on N.5 + N.5b. Legacy renderer retirement was pulled forward
   into N.5 ship amendment — `InstancedMeshRenderer`, `StaticMeshRenderer`,
   `WbFoundationFlag` are gone — and the terrain legacy renderer
@@ -676,8 +677,8 @@ for our deletions/additions; merge upstream `master` periodically.
   is a candidate), GPU-side culling via compute pre-pass (eliminates
   the per-frame slot walk + DEIC build entirely), GL_TIME_ELAPSED query
   double-buffering (deferred from N.5 — diagnostic shows `gpu_us=0/0`
-  under `ACDREAM_WB_DIAG=1`), direct higher-radius perf comparison once
-  A.5 lands (where modern's architectural wins manifest), retire the
+  under `ACDREAM_WB_DIAG=1`), direct higher-radius perf comparison (A.5
+  has now landed — modern's architectural wins are measurable), retire the
   legacy `Texture2D`/`sampler2D` path in `TextureCache` (currently kept
   for Sky + Debug + particle paths now that Terrain has migrated).
   Plan + spec written when work begins. **Estimate: 1-2 weeks.**