Zero Hour engine — macOS (Apple Silicon) engine-v0.1.9

engine-v0.1.9 — memory-leak fixes: in-game plateau + no-leak menu option

Native macOS (Apple Silicon) build of the Zero Hour engine. This release stops the
long-session memory growth, in-game and in the menu.

IN-GAME MEMORY GROWTH — FIXED
Symptom: a session started around 950 MB and ratcheted to 2–4+ GB; units died off
late in a match but memory kept climbing, and leaving to the menu added another
~200 MB. Now it plateaus at the battle working set (~1.2–1.5 GB) and recovers
after the match.

Symptom → cause → fix:

1. Pool policy = cap-not-decay. Cause: periodically freeing the renderer's GPU
   buffer/texture recycle pools was itself the main leak — on Apple Metal each
   release of a churned pooled resource becomes a permanent "zombie" backing in
   the driver's own never-shrinking pool, while the next allocation takes fresh
   device memory (A/B: freeing ratcheted ~13 MB/min; not-freeing was flat at half
   the size). Fix: never free in steady state (the pools plateau at the working
   set, as the original game does); bound load bursts with flat 256-per-key caps.
2. Pool thread-safety. Cause: the background texture loader raced the render
   thread on unguarded pool maps; corrupted lookups orphaned textures (29k /
   2.5 GB in one session). Fix: guard all pool operations with a mutex.
3. Audio AudioUnit accumulation. Cause: re-binding a sound file detached a still-
   playing node, so the audio engine kept its AudioUnit alive (+559 per 3 min of
   battle). Fix: stop the node before detaching, in both the 2D and 3D paths.
4. Map-load GPU balloon. Cause: hundreds of mipmap generations in a single
   command buffer made the driver size its pool at the burst peak (~200 MB) and
   never shrink. Fix: chunk mip flushes (≤32 per command buffer) with completion
   backpressure.
5. Bot/External-API AIGroup leak: an AI group was created per bot command and
   never destroyed. Fix: RAII releaser on every exit path.
6. Bot/External-API WebSocket backpressure: a slow /events consumer grew an
   unbounded in-process send buffer. Fix: skip clients with >4 MB queued (the
   event stream is resumable).
7. Guard-from-Position use-after-free: leaving a match mid-targeting left a decal
   pointing into the torn-down shadow manager. Fix: clear the targeting state on
   reset.

MENU 3D SCENE (SHELLMAP) — NEW OPT-OUT
Symptom: sitting in the main menu with the animated 3D background grew memory
~130 MB/min (a macOS AGX-driver behaviour tied to the shellmap scene, invariant to
every render/pool knob we tried). Fix: a new GEN_NO_SHELLMAP hook disables just
that scene (static menu background instead), applied after INI loads so a mod's
ShellMapOn setting can't silently re-enable it. The macOS launcher's "Disable menu
3D scene" option (on by default, launcher-v0.1.5) uses it. Note: the engine's
native -noshellmap command-line flag does NOT work with total-conversion mods —
it is parsed before INI, so the mod re-enables the scene.

Apple Silicon (M-series) only. You must own a legitimate copy of Zero Hour — EA
game data is not included. Checksums in SHA256SUMS.