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.

docs/screens/realism/2026-11-01-forward-plus/report.json

@@ -0,0 +1,82 @@
+{
+  "run": "docs/screens/realism/2026-11-01-forward-plus-eval",
+  "judge_model": null,
+  "sets": {
+    "baseline": {
+      "entrance_late": {
+        "target": "docs/screens/concepts/hollywood_entrance_rain_night.png",
+        "metrics": {
+          "edge_density": 21.3,
+          "fine_detail": 9.55,
+          "contrast": 68.03,
+          "saturation_mean": 127.45,
+          "colour_spread": 67.44
+        },
+        "target_metrics": {
+          "edge_density": 8.43,
+          "fine_detail": 3.51,
+          "contrast": 27.34,
+          "saturation_mean": 159.44,
+          "colour_spread": 26.61
+        },
+        "metric_gap": 1.568
+      },
+      "street_late": {
+        "target": "docs/screens/concepts/boulevard_skyline_dusk.png",
+        "metrics": {
+          "edge_density": 10.57,
+          "fine_detail": 6.21,
+          "contrast": 26.84,
+          "saturation_mean": 74.1,
+          "colour_spread": 26.55
+        },
+        "target_metrics": {
+          "edge_density": 8.83,
+          "fine_detail": 4.61,
+          "contrast": 33.26,
+          "saturation_mean": 188.16,
+          "colour_spread": 35.38
+        },
+        "metric_gap": 0.247
+      }
+    },
+    "candidate": {
+      "entrance_late": {
+        "target": "docs/screens/concepts/hollywood_entrance_rain_night.png",
+        "metrics": {
+          "edge_density": 19.31,
+          "fine_detail": 8.37,
+          "contrast": 55.27,
+          "saturation_mean": 104.53,
+          "colour_spread": 54.55
+        },
+        "target_metrics": {
+          "edge_density": 8.43,
+          "fine_detail": 3.51,
+          "contrast": 27.34,
+          "saturation_mean": 159.44,
+          "colour_spread": 26.61
+        },
+        "metric_gap": 1.187
+      },
+      "street_late": {
+        "target": "docs/screens/concepts/boulevard_skyline_dusk.png",
+        "metrics": {
+          "edge_density": 11.4,
+          "fine_detail": 6.21,
+          "contrast": 27.58,
+          "saturation_mean": 77.86,
+          "colour_spread": 27.49
+        },
+        "target_metrics": {
+          "edge_density": 8.83,
+          "fine_detail": 4.61,
+          "contrast": 33.26,
+          "saturation_mean": 188.16,
+          "colour_spread": 35.38
+        },
+        "metric_gap": 0.258
+      }
+    }
+  }
+}

docs/screens/realism/2026-11-01-forward-plus/report.md

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+# Realism report: `docs/screens/realism/2026-11-01-forward-plus`
+
+| set | shot | target | gap ↓ | edges | detail | contrast | overall | lighting | materials | texture | backdrop |
+| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
+| baseline | entrance_late | hollywood_entrance_rain_night | 1.568 | 21.3 | 9.55 | 68.03 | - | - | - | - | - |
+| baseline | street_late | boulevard_skyline_dusk | 0.247 | 10.57 | 6.21 | 26.84 | - | - | - | - | - |
+| candidate | entrance_late | hollywood_entrance_rain_night | 1.187 | 19.31 | 8.37 | 55.27 | - | - | - | - | - |
+| candidate | street_late | boulevard_skyline_dusk | 0.258 | 11.4 | 6.21 | 27.58 | - | - | - | - | - |
+
+Mean scores per set (all captured shots):
+
+| set | shots | gap ↓ | overall | lighting | materials | texture_detail | backdrop | characters |
+| --- | --- | --- | --- | --- | --- | --- | --- | --- |
+| baseline | 2 | 0.907 | - | - | - | - | - | - |
+| candidate | 2 | 0.723 | - | - | - | - | - | - |
+
+
+## Desktop HQ A/B
+
+`baseline` is the normal GL Compatibility build; `candidate` is the same
+staging with `packaging/desktop_hq/override.cfg` beside the project (Forward+,
+SDFGI and volumetric fog). Both use `--stages=late --flashlight`.
+
+The entrance metric gap improved **1.568 → 1.187** and the two-shot mean
+**0.907 → 0.723**. The flashlight now lights the door instead of disappearing
+into the dark, while the LATE volumetric density (0.020) leaves the brick
+facade readable instead of washing it out. `street_late` is nearly unchanged
+(0.247 → 0.258), which is expected because the fog is tuned around the
+entrance.
+
+Capture command:
+
+```bash
+cp packaging/desktop_hq/override.cfg ./override.cfg
+xvfb-run -a godot --path . --script res://src/test/capture_realism.gd -- \
+  --stages=late --flashlight \
+  --out=res://docs/screens/realism/2026-11-01-forward-plus/candidate
+rm override.cfg
+```
+
+The vision judge could not run because `OPENROUTER_API_KEY` is invalid; the
+retry is recorded in `TODO.md`.