Fix duplicate schema definitions causing YAML validation issues

Fixes #14122

Author: gordonwoodhull

src/resources/schema/definitions.yml

@@ -2752,8 +2752,9 @@
 - id: logo-light-dark-specifier-path-optional
   description: >
     Any of the ways a logo can be specified: string, object, or light/dark object of
-    string or object
+    string or object. Use `false` to explicitly disable the logo.
   anyOf:
+    - enum: [false]
     - ref: logo-specifier-path-optional
     - object:
         closed: true

src/resources/schema/document-epub.yml

@@ -35,25 +35,6 @@
     ref: epub-contributor
   description: Contributors to this publication.
 
-- name: subject
-  tags:
-    formats: [$epub-all]
-  schema:
-    anyOf:
-      - string
-      - object:
-          closed: true
-          properties:
-            text:
-              string:
-                description: The subject text.
-            authority:
-              string:
-                description: An EPUB reserved authority value.
-            term:
-              string:
-                description: The subject term (defined by the schema).
-  description: The subject of the publication.
 
 - name: type
   tags:

src/resources/schema/document-metadata.yml

@@ -6,9 +6,23 @@
   description: "List of keywords to be included in the document metadata."
 
 - name: subject
-  schema: string
+  schema:
+    anyOf:
+      - string
+      - object:
+          closed: true
+          properties:
+            text:
+              string:
+                description: The subject text.
+            authority:
+              string:
+                description: An EPUB reserved authority value.
+            term:
+              string:
+                description: The subject term (defined by the schema).
   tags:
-    formats: [$pdf-all, $office-all, odt]
+    formats: [$pdf-all, $office-all, odt, $epub-all]
   description: "The document subject"
 
 - name: description

tests/docs/schema-files/2026/03/01/logo-false.yml

@@ -0,0 +1,3 @@
+schema:
+  ref: logo-light-dark-specifier-path-optional
+value: false

tests/docs/smoke-all/2026/03/01/subject-structured-epub.qmd

@@ -0,0 +1,18 @@
+---
+title: Test
+subject:
+  text: "Science"
+  authority: "BISAC"
+  term: "SCI000000"
+format: epub
+_quarto:
+  tests:
+    epub:
+      ensureEpubFileRegexMatches:
+        - path: EPUB/content.opf
+          regexes:
+            - ['dc:subject id="subject-1">Science</dc:subject>', 'property="authority">BISAC', 'property="term">SCI000000']
+            - []
+---
+
+Test structured subject metadata in epub output.