Publish the mood-tag layout schema its own description relies on

The annotation was already in the assigning form and still never reached
the document, because both consumers extend the base rather than
reference it and .extend() builds a new object. Same shape as Medication
and CoachPrefs, same remedy: name it in the forced-registration block.

docs/api/openapi.yaml

@@ -68573,6 +68573,34 @@ components:
         - showEvidenceByDefault
         - defaultWindow
       additionalProperties: false
+    MoodTagLayout:
+      type: object
+      properties:
+        groupOrder:
+          maxItems: 50
+          type: array
+          items:
+            type: string
+            minLength: 1
+            maxLength: 80
+        placements:
+          type: object
+          propertyNames:
+            type: string
+            minLength: 1
+            maxLength: 80
+          additionalProperties:
+            type: array
+            items:
+              type: string
+              minLength: 1
+              maxLength: 80
+      additionalProperties: false
+      description: "Per-user mood-tag presentation blob. `groupOrder`: category keys in display order (unknown dropped,
+        missing appended in seeded order). `placements`: categoryKey → ordered tag keys; a placed tag renders in that
+        group at that index, un-placed tags follow in their home category. Display-only — placements referencing
+        hidden/archived/unknown keys are silently dropped at read time. Both fields optional: PUT merges
+        preserve-when-absent."
   parameters:
     AccountSelector:
       name: X-HealthLog-Account