options: Interior Darkness says what it does not scale

grom turned this dial down, hit snow in Dun Morogh, and got rooms that read
"really grey and flat" — then spent his own time hunting it before settling on
19% by trial. The dial was not lying, it was just silent about the half of the
picture it does not own.

A storm's fog reaches indoors at full strength, which is faithful: the MFOG
selector bails on a one-record root (`0x69de4b`) so the room keeps the SCENE
fog, and the crossfade staged at `0x6cef43` carries it in "storm veil included".
Measured at his own spot, snow against clear: the fog start goes 0 -> -105 over a
350 end, which is 23.1% fog at ZERO distance — the wall in front of you. That
predicts [36.0, 50.2, 57.8] against a measured [36.9, 50.3, 58.0], so it is the
whole effect. Turn the room light down under that and the veil is most of what
is left.

So the tooltip now says it, in both locales, and points at the dial as the answer
instead of leaving the next player to re-derive it. No behaviour changes — the
fog is the reference's and stays.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01SgstFWtn1RxEJ5kVrpgYwn

crates/benilla-app/assets/ui/OptionsFrame.xml

@@ -672,7 +672,11 @@
                     INTERIOR_DARKNESS =
                         "Scales interior fixture light and room ambient, including the light from "
                         .. "lamps and candles. Lower values make both dimmer.\n\n"
-                        .. "1.0 leaves these inputs unchanged. Free at any setting.",
+                        .. "1.0 leaves these inputs unchanged. Free at any setting.\n\n"
+                        .. "It does not scale the weather. A storm's fog reaches indoors at full "
+                        .. "strength, as it does in the original client, so with this turned well "
+                        .. "down in bad weather that fog is most of what is left and rooms read "
+                        .. "flat and grey. Raise this rather than hunt for the cause elsewhere.",
                     -- MONKEY (p0 skyDither)
                     SKY_DITHER =
                         "Adds a faint noise to the final image so smooth sky and fog gradients do not "
@@ -945,7 +949,11 @@
                     INTERIOR_DARKNESS =
                         "Масштабирует свет светильников и фоновое освещение помещений, включая "
                         .. "свет ламп и свечей. Меньшие значения ослабляют и то и другое.\n\n"
-                        .. "1.0 оставляет эти составляющие без изменений. Ничего не стоит при любом значении.",
+                        .. "1.0 оставляет эти составляющие без изменений. Ничего не стоит при любом значении.\n\n"
+                        .. "Погоды не касается: туман непогоды проникает внутрь в полную силу, как "
+                        .. "и в оригинальном клиенте. При сильно пониженном значении в плохую "
+                        .. "погоду именно этот туман и остаётся, и помещения выглядят плоско и "
+                        .. "серо. Поднимите этот ползунок, а не ищите причину в другом месте.",
                     -- MONKEY (p0 skyDither)
                     SKY_DITHER =
                         "Добавляет едва заметный шум в итоговое изображение, чтобы плавные переходы цвета "