Fix wiki-publish: clean stale wiki pages before copying generated content

The workflow was not removing old wiki pages before copying freshly
generated ones. When Java classes were renamed or deleted, their
corresponding wiki pages persisted because only new/updated files were
copied over the existing wiki repo.

Add a find-delete step to remove all existing .md files from the wiki
repo before copying, so git add -A properly tracks deletions alongside
additions and modifications.

Co-authored-by: mercyblitz <533114+mercyblitz@users.noreply.github.com>
Agent-Logs-Url: https://github.com/microsphere-projects/microsphere-java/sessions/e3c5a18a-8246-4b36-a700-fa2fd4a54335

Author: Copilot

.github/workflows/wiki-publish.yml

@@ -55,6 +55,9 @@ jobs:
 
       - name: Copy generated pages to wiki
         run: |
+          # Remove all existing markdown files from wiki repo to ensure
+          # pages for renamed or deleted classes are properly cleaned up
+          find wiki-repo -maxdepth 1 -name '*.md' -type f -delete 2>/dev/null || true
           # Copy all generated markdown files to the wiki repo
           cp wiki-output/*.md wiki-repo/
           echo "Copied wiki pages to wiki repository"