fix(workflow): wiki-mirror jobs request the wiki: write token scope (#192)

The job token got HTTP 403 creating the first wiki page: Gitea gives the wiki its own
permission scope, which contents: write does not cover.

Files changed:
- .gitea/scripts/wiki-push.sh
- .gitea/workflows/release.yml
- .gitea/workflows/wiki-mirror.yml

Co-Authored-By: Claude Code <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01SnAJ7Z3CpVD3PRbN73QtU2

.gitea/workflows/wiki-mirror.yml

@@ -29,6 +29,7 @@ jobs:
       image: debian:trixie-slim
     permissions:
       contents: write
+      wiki: write
     env:
       PUBLIC_BASE_URL: https://gitea.nehmer.net