feat: Rec Royale night mode (ClientMod) + admin switch to give baked RRO rooms a data blob

ClientMod (2023-03-21): opt-in Rec Royale night mode. RRO scenes never
enable the room mood engine (no data blob → SceneMoodSettings.isEnabled
stays false, CurrentMood null, the per-frame update returns at once), so
the mod replays the room-data loader's bring-up, registers a shipped
night MoodSetting (Night_Calm_Outdoor_Mood by default) as the scene's
default mood, supplies a skybox material on the Custom/SkyBox shader
(MoodConfig.SkyBoxMaterial is not loaded outside custom rooms), assigns
the scene's directional light as RenderSettings.sun, matches the key
light to the engine-driven sun, darkens via the mood's post-exposure and
sun/ambient intensities, forces post-processing on, keeps or disables
fog, hides the daytime cloud meshes, unlocks weapon flashlights, and
restores everything on hotkey-off / scene change. All knobs live in
dorknet-clientmod.json (RecRoyaleNight*), written by install-melon.ps1.

Server/admin: baked Rec Room Originals are seeded with an empty
DataBlobName, which the 2023 client reads as "no room data" — no Maker
Pen, no CV2 room-settings chips, no saves, and for Rec Royale no game at
all (its game-rule chip RecRoyaleSolos_GameRuleWrapperCircuit ships in
the blob, not the scene). New admin actions on the Sub-rooms tab:
POST rooms/{id}/subrooms/{sub}/blob/enable stamps the synthetic default
blob name (which CdnController already answers with the RRO-editable
blob) and blob/reset clears it back to scene-only. IsRRO is derived from
IsAGRoom, so the client keeps loading the baked map.

Docs: README section, docs/admin.md procedure, docs/recroom-2023-room-save.md,
new docs/recroom-2023-scene-moods.md with the ISIL offsets behind all of it.
Tests: RroRoomBlobTests.

DorkNet.ClientMod/dorknet-clientmod.json.template

@@ -11,5 +11,18 @@
     "GoldenTrophy",
     "IsleOfLostSkulls",
     "TheRiseofJumbotron"
-  ]
+  ],
+  "RecRoyaleNightMode": false,
+  "RecRoyaleNightMood": "Night_Calm_Outdoor_Mood",
+  "RecRoyaleNightScenes": ["RecRoyale"],
+  "RecRoyaleNightFlashlights": true,
+  "RecRoyaleNightFog": false,
+  "RecRoyaleNightExposure": -3.5,
+  "RecRoyaleNightSunScale": 0.15,
+  "RecRoyaleNightAmbientScale": 0.2,
+  "RecRoyaleNightForcePostProcessing": true,
+  "RecRoyaleNightMatchSunLights": true,
+  "RecRoyaleNightDisableFog": false,
+  "RecRoyaleNightHideObjects": ["Cloud"],
+  "RecRoyaleNightToggleKey": ""
 }