Add the optional Forward+ desktop HQ build

Package a Forward+ preset with volumetric fog, SDFGI and a volumetric flashlight
for a separate Linux/Windows Desktop HQ zip. Gate the effects on a real
RenderingDevice, tune LATE fog, and adapt local light falloff for Godot 4.7.
Record the Compatibility/Forward+ A/B captures and metrics, add the artifact to
the build/publish scripts, and keep the default Compatibility/Web path
unchanged. Headless 231/231, Python 87/87; exported HQ binary boots with Vulkan.

MEMORY.md

@@ -44,6 +44,15 @@ Session memory for durable decisions, state, and gotchas. Keep concise, remove o
 - Shift length is the scenario's `shift_duration_s` (900 s in all three venues). Tests and the screenshot tool override elapsed time; they do not change the default.
 - RNG: NPC reactions and event scheduling are seedable for deterministic tests.
 
+- **Desktop HQ preset (v0.7.1):** `packaging/desktop_hq/override.cfg` switches a
+  copied executable to Forward+; `Materials.forward_plus_active()` gates
+  volumetric fog/SDFGI and `light_volumetric_fog_energy`, and
+  `Materials.modern_light_falloff()` compensates for Godot 4.7's much harsher
+  local-light falloff. LATE volumetric density is 0.020 with flashlight
+  volumetric energy 3.0. `tools/build_releases.sh` packages the Linux/Windows
+  binaries + override into `gig-line-desktop-hq-<version>.zip`;
+  `publish_release.sh` uploads it when present. A/B report:
+  `docs/screens/realism/2026-11-01-forward-plus/` (entrance gap 1.568→1.187).
 - **Local Godot toolchain (2026-11-01):** `~/.local/bin/godot` is 4.7.2 stable;
   4.3 stable is kept as `~/.local/bin/godot-4.3.stable`. Export templates for
   4.7.2 are installed under `~/.local/share/godot/export_templates/4.7.2.stable`