Fixes#160: update_wiki_page was renaming pages to "unnamed"
Root causes:
1. page_name wasn't URL-encoded, breaking pages with special chars like ':'
2. PATCH request was missing 'title' field, causing Gitea to use default name
Changes:
- Add URL encoding (urllib.parse.quote) to get_wiki_page, update_wiki_page, delete_wiki_page
- Add 'title': page_name to update_wiki_page payload to preserve page name
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
