feat(c3): the scene descriptor crosses — timeOfDay closes two gaps (forge half)

C3/P4 forge half. `zones[].scene` — the descriptor the client''s diorama binds to.

STABLE KEYS ONLY, and the exclusions are the design. RG-C: HD-2D''s look is wholly
client-side, so the sim owes a DESCRIPTOR not a layout (Takahashi/Miyauchi 2018),
and state flags swap lighting and dressing variants, NEVER layout (Triangle
Strategy). So `parallaxLayers`, `skylineRef`, `collisionType`, the physics fields
and the sky/light hints are deliberately NOT here and stay `no-channel` — a
descriptor carrying them would be a renderer config crossing a sim boundary.

Nothing new is invented: `biome` comes from the existing `biome:` tag convention
(the same idiom as `mode:` and `faction:`), `timeOfDay` is already authored, and
`dressingDensity` is a coarse three-bucket read of interactable count — ordinal
because the client decides what density means and a continuous number would imply
precision the author never had.

⚠ ONE FIELD CLOSED TWO GAPS. C0 filed `zones[].timeOfDay` as `no-channel` with the
note "no channel — even though the SpawnCondition grammar has a `time:` operand the
engine could gate on." That parenthetical named the second gap without knowing it:
C3/P2 measured `time-of-day` as an UNEVALUABLE gate operand for exactly this
reason. The descriptor gives the field its channel, and that channel is the missing
input the operand needed.

THE RECOUNT: no-channel 170 -> 169, carried-lossless 189 -> 190, total 377, all
verified.

Suite 2431, unchanged.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

Author: mcp-tool-shop

docs/c0-alignment/export-table.json

@@ -15,15 +15,15 @@
   "tally": {
     "total": 377,
     "byClass": {
-      "no-channel": 170,
-      "carried-lossless": 189,
+      "no-channel": 169,
+      "carried-lossless": 190,
       "carried-approximated": 18
     },
     "byChannel": {
-      "none": 170,
+      "none": 169,
       "assetPacks": 11,
       "assets": 11,
-      "contentPack": 169,
+      "contentPack": 170,
       "packMeta": 6,
       "assetBindings": 7,
       "manifest": 3
@@ -4181,14 +4181,14 @@
     },
     {
       "path": "zones[].timeOfDay",
-      "class": "no-channel",
-      "channel": "none",
-      "packPath": null,
-      "transform": null,
-      "absenceProof": "key-absent",
+      "class": "carried-lossless",
+      "channel": "contentPack",
+      "packPath": "zones[].scene.timeOfDay",
+      "transform": "moved-into-scene-descriptor",
+      "absenceProof": null,
       "verified": true,
-      "evidence": "key \"timeOfDay\" absent from all six export artifacts",
-      "note": "Time-of-day key: no channel — even though the SpawnCondition grammar has a `time:` operand the engine could gate on."
+      "evidence": "transform \"moved-into-scene-descriptor\" → contentPack:zones[].scene.timeOfDay (3 values); semantics asserted separately",
+      "note": "CLOSED BY C3/P4. Lands on the scene descriptor the client's diorama binds to — a STABLE KEY, not prose. Also supplies the input the `time-of-day` gate operand was measured missing."
     }
   ]
 }

docs/c0-alignment/export-table.md

@@ -2,7 +2,7 @@
 
 Generated by `packages/export-ai-rpg/src/__tests__/c0-export-table.test.ts`. Do not hand-edit.
 
-Schema version 4.5.0. Tally: {"no-channel":170,"carried-lossless":189,"carried-approximated":18}.
+Schema version 4.5.0. Tally: {"no-channel":169,"carried-lossless":190,"carried-approximated":18}.
 
 | Field | Class | Channel | Image | Note |
 |---|---|---|---|---|
@@ -382,4 +382,4 @@ Schema version 4.5.0. Tally: {"no-channel":170,"carried-lossless":189,"carried-a
 | `zones[].stratumId` | no-channel | none | — | The zone→stratum membership link, dropped along with the strata themselves. |
 | `zones[].tags[]` | carried-lossless | contentPack | `zones[].tags[]` | The single richest carried zone field — the engine reads tags as spawn, chokepoint, ambush and safe-zone gates. |
 | `zones[].tilesetId` | carried-lossless | assetBindings | `zones{}.tilesetId` | Same channel caveat as backgroundId. |
-| `zones[].timeOfDay` | no-channel | none | — | Time-of-day key: no channel — even though the SpawnCondition grammar has a `time:` operand the engine could gate on. |
+| `zones[].timeOfDay` | carried-lossless | contentPack | `zones[].scene.timeOfDay` *(moved-into-scene-descriptor)* | CLOSED BY C3/P4. Lands on the scene descriptor the client's diorama binds to — a STABLE KEY, not prose. Also supplies the input the `time-of-day` gate operand was measured missing. |

docs/c0-alignment/fixture-manifest.json

@@ -21,5 +21,5 @@
   "contentPacks": [
     "c0-vocabulary-coverage"
   ],
-  "contentHash": "sha256:63fde4f7eaaec7320548b3ac0a05fc2cf758336e3a7c11d1c6d3ef6f4768ea25"
+  "contentHash": "sha256:375ffb5c4afc51ad65216902234051c702e364018c8c6a70285b6bd8aafce283"
 }

docs/c0-alignment/fixture-pack.json

@@ -167,7 +167,11 @@
       },
       "hazardRefs": [
         "hazard-scalding-steam"
-      ]
+      ],
+      "scene": {
+        "timeOfDay": "dusk",
+        "dressingDensity": "normal"
+      }
     },
     {
       "id": "zone-under-vault",
@@ -243,7 +247,11 @@
       "hazardRefs": [
         "hazard-black-water",
         "hazard-void-drop"
-      ]
+      ],
+      "scene": {
+        "timeOfDay": "night",
+        "dressingDensity": "normal"
+      }
     },
     {
       "id": "zone-sky-gantry",
@@ -304,7 +312,11 @@
       },
       "hazardRefs": [
         "hazard-void-drop"
-      ]
+      ],
+      "scene": {
+        "timeOfDay": "day",
+        "dressingDensity": "normal"
+      }
     }
   ],
   "districts": [

packages/export-ai-rpg/src/__tests__/c0/export-table-data.ts

@@ -271,7 +271,13 @@ export const EXPLICIT_ROWS: ExportRow[] = [
   { path: 'zones[].directionalLightYaw', class: 'no-channel', absence: { kind: 'key-absent', key: 'directionalLightYaw' }, note: 'Lighting hint: no channel.' },
   { path: 'zones[].directionalLightPitch', class: 'no-channel', absence: { kind: 'key-absent', key: 'directionalLightPitch' }, note: 'Lighting hint: no channel.' },
   { path: 'zones[].skyLightIntensity', class: 'no-channel', absence: { kind: 'key-absent', key: 'skyLightIntensity' }, note: 'Lighting hint: no channel.' },
-  { path: 'zones[].timeOfDay', class: 'no-channel', absence: { kind: 'key-absent', key: 'timeOfDay' }, note: 'Time-of-day key: no channel — even though the SpawnCondition grammar has a `time:` operand the engine could gate on.' },
+  // ⚠ FLIPPED BY C3/P4, and this row closed TWO gaps with one field. C0's note —
+  // "no channel — even though the SpawnCondition grammar has a `time:` operand the
+  // engine could gate on" — named the second one without knowing it: C3/P2
+  // measured `time-of-day` as an UNEVALUABLE gate operand precisely because
+  // nothing tracked time of day. The scene descriptor gives `timeOfDay` its
+  // channel, and that channel is the missing input the operand needed.
+  { path: 'zones[].timeOfDay', class: 'carried-lossless', channel: 'contentPack', packPath: 'zones[].scene.timeOfDay', transform: 'moved-into-scene-descriptor', note: 'CLOSED BY C3/P4. Lands on the scene descriptor the client\'s diorama binds to — a STABLE KEY, not prose. Also supplies the input the `time-of-day` gate operand was measured missing.' },
   { path: 'zones[].collisionType', class: 'no-channel', absence: { kind: 'key-absent', key: 'collisionType' }, note: 'Collision channel hint: no channel.' },
 
   // ── Districts ───────────────────────────────────────────────────────

packages/export-ai-rpg/src/convert-zones.ts

@@ -28,13 +28,67 @@ export type ExportedEntryGate = {
   reason?: string;
 };
 
+/** The scene descriptor the client's diorama binds to (C3/P4). Stable keys only. */
+export type ExportedScene = {
+  biome?: string;
+  timeOfDay?: string;
+  dressingDensity?: 'sparse' | 'normal' | 'dense';
+  variantTags?: string[];
+};
+
 /** The engine's `ZoneDefinition` plus the unpublished C3 fields. See {@link ExportedEntryGate}. */
 export type ExportedZone = ZoneDefinition & {
   entryGate?: ExportedEntryGate;
   /** C3/P3 — ids into the pack's `hazardDefinitions`. */
   hazardRefs?: string[];
+  /** C3/P4 — the scene descriptor. */
+  scene?: ExportedScene;
 };
 
+/**
+ * Build a zone's scene descriptor from the keys the schema ALREADY authors
+ * (C3/P4).
+ *
+ * ⚠ NOTHING NEW IS INVENTED HERE, which is the point. The forge has carried
+ * `timeOfDay` and `tags` since before this cycle; C0 filed `zones[].timeOfDay` as
+ * `no-channel` with the note "no channel — even though the SpawnCondition grammar
+ * has a `time:` operand the engine could gate on." This closes both at once: the
+ * descriptor gives `timeOfDay` its channel, and that channel is the missing input
+ * the `time-of-day` gate operand needed (C3/P2 measured it unevaluable for exactly
+ * this reason).
+ *
+ * ⚠ AND WHAT IS DELIBERATELY EXCLUDED. `parallaxLayers`, `skylineRef`,
+ * `collisionType`, the physics fields and the sky/light hints are NOT here. They
+ * are client-owned per the charter and stay `no-channel` in the recount. A
+ * descriptor that carried them would be a renderer config crossing a simulation
+ * boundary — the exact thing Triangle Strategy's "swap dressing, never layout"
+ * rule forbids.
+ *
+ * `biome` is derived from the zone's authored tags rather than invented: the first
+ * `biome:`-prefixed tag, if any. Tag conventions are how this schema already
+ * expresses `mode:` and `faction:`, so this adds no new authoring surface.
+ */
+function buildScene(z: {
+  tags: string[];
+  timeOfDay?: string;
+  interactables: unknown[];
+  propPlacements?: unknown[];
+}): ExportedScene | undefined {
+  const biomeTag = z.tags.find((t) => t.startsWith('biome:'));
+  // Coarse and ORDINAL — three buckets, because the client decides what density
+  // means and a continuous number would imply a precision the author never had.
+  const propCount = z.interactables.length;
+  const dressingDensity: ExportedScene['dressingDensity'] =
+    propCount === 0 ? 'sparse' : propCount >= 3 ? 'dense' : 'normal';
+
+  const scene: ExportedScene = {
+    ...(biomeTag ? { biome: biomeTag.slice('biome:'.length) } : {}),
+    ...(z.timeOfDay !== undefined ? { timeOfDay: z.timeOfDay } : {}),
+    dressingDensity,
+  };
+  return Object.keys(scene).length > 0 ? scene : undefined;
+}
+
 /**
  * Convert project zones → engine `ZoneDefinition[]`.
  *
@@ -193,6 +247,8 @@ export function convertZones(project: WorldProject, warnings?: string[]): Export
       // mean anything without pack code. C0 measured that difference across twelve
       // worlds and the contrast is preserved deliberately.
       hazardRefs: z.hazardRefs && z.hazardRefs.length > 0 ? [...z.hazardRefs] : undefined,
+      // C3/P4 — the scene descriptor, built from keys already authored.
+      scene: buildScene(z),
     };
   });
 }