Fix local playbook to use local filesystem instead of GitHub main

The playbook was pulling from GitHub's main branch instead of the local
working directory, causing the build to show old remote/* pages instead
of the new managed/* structure.

Changed content source from GitHub URL to local directory (.) with HEAD
branch so Antora builds from the current branch with all local changes.

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

Author: 2 people

local-antora-playbook.yml

@@ -12,8 +12,8 @@ output:
   clean: true
 content:
   sources:
-  - url: https://github.com/redpanda-data/adp-docs
-    branches: main
+  - url: .
+    branches: HEAD
   - url: https://github.com/redpanda-data/docs
     branches: [main, v/*, api, shared, site-search,'!v-end-of-life/*']
   - url: https://github.com/redpanda-data/cloud-docs