feat(quotesdb): add hidden field to openapi spec

Add `hidden` (boolean, required) to the Quote response schema so all
GET responses reflect the field. Add `hidden` (boolean, optional) to
QuoteUpdateRequest so callers can toggle visibility via POST /api/quotes/:id.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

quotesdb/api/openapi.yaml

@@ -49,6 +49,7 @@ components:
         - text
         - author
         - tags
+        - hidden
         - created_at
         - updated_at
       properties:
@@ -79,6 +80,12 @@ components:
             type: string
           description: Zero or more tags attached to the quote.
           example: ["work", "inspiration"]
+        hidden:
+          type: boolean
+          description: >
+            When true, the quote is suppressed from public list and random
+            endpoints. Hidden quotes can still be fetched directly by ID.
+          example: false
         created_at:
           type: string
           format: date-time
@@ -161,6 +168,11 @@ components:
           items:
             type: string
           description: Replacement tag list. Replaces all existing tags.
+        hidden:
+          type: boolean
+          description: >
+            Set to true to hide the quote from public list and random endpoints,
+            or false to make it visible again.
 
     # Paginated list of quotes.
     QuoteList: