fix(mood): report the tag and factor keys a mood write did not store

An unknown or archived tag key, or a factor the catalog no longer carries,
was dropped on the way in while the entry still reported "inserted" (bulk)
or 201 (create, edit). A client had no way to tell that part of what it sent
never landed.

Each write now names those keys: the bulk result per entry, the create and
edit responses on the entry, as droppedTagKeys and droppedFactorKeys. Both
are present only when non-empty, so a response where everything landed is
unchanged. An archived tag an edit preserved is on the entry and is not
listed. The web shows a short notice after saving when a picked tag was left
off.

docs/api/openapi.yaml

@@ -60081,6 +60081,19 @@ components:
         externalId:
           description: Echoed back when the entry carried one, for client mapping.
           type: string
+        droppedTagKeys:
+          description: "`tagKeys` from this request that were not stored: unknown to the catalog, archived, another account's
+            custom tag, or a rated factor sent as a binary key. Present only when non-empty; absent means every
+            submitted key landed. The entry itself was written."
+          type: array
+          items:
+            type: string
+        droppedFactorKeys:
+          description: "`ratedFactors` keys from this request that were not stored: unknown, archived, or not a rated factor.
+            Present only when non-empty; absent means every submitted factor landed."
+          type: array
+          items:
+            type: string
       required:
         - index
         - status
@@ -60722,6 +60735,19 @@ components:
             - $ref: "#/components/schemas/MoodContextOutput"
             - type: "null"
           description: The day's context, or null when the entry carries none. Null and an object of nulls are different answers.
+        droppedTagKeys:
+          description: "Create and edit responses only: `tagKeys` from the request that are not on the entry (unknown, archived,
+            another account's custom tag, or a rated factor sent as a binary key). Present only when non-empty. An
+            archived tag the edit preserved is on the entry and is not listed."
+          type: array
+          items:
+            type: string
+        droppedFactorKeys:
+          description: "Create and edit responses only: `ratedFactors` keys from the request that are not on the entry. Present
+            only when non-empty."
+          type: array
+          items:
+            type: string
       required:
         - id
         - userId