Correctly count tag categories

If multiple tags of the same category are applied to the same item,
just summing tag counts will produce the wrong results as now items
are counted multiple times.

modules/restapi/src/main/resources/docspell-openapi.yml

@@ -4242,6 +4242,7 @@ components:
       required:
         - count
         - tagCloud
+        - tagCategoryCloud
         - fieldStats
         - folderStats
       properties:
@@ -4250,6 +4251,8 @@ components:
           format: int32
         tagCloud:
           $ref: "#/components/schemas/TagCloud"
+        tagCategoryCloud:
+          $ref: "#/components/schemas/NameCloud"
         fieldStats:
           type: array
           items:
@@ -4354,7 +4357,7 @@ components:
             $ref: "#/components/schemas/TagCount"
     TagCount:
       description: |
-        Generic structure for counting something.
+        Structure for counting tags.
       required:
         - tag
         - count
@@ -4364,6 +4367,30 @@ components:
         count:
           type: integer
           format: int32
+
+    NameCloud:
+      description: |
+        A set of counters.
+      required:
+        - items
+      properties:
+        items:
+          type: array
+          items:
+            $ref: "#/components/schemas/NameCount"
+    NameCount:
+      description: |
+        Generic structure for counting something.
+      required:
+        - name
+        - count
+      properties:
+        name:
+          type: string
+        count:
+          type: integer
+          format: int32
+
     AttachmentMeta:
       description: |
         Extracted meta data of an attachment.