Use a dedicated PAT for Gitea package registry uploads

The automatic Actions token (GITEA_TOKEN) returns 401 against the
packages content API in this Gitea version, and GITEA_/GITHUB_-
prefixed names are reserved for secrets anyway. Switch to a
dedicated write:package-scoped token stored as PKG_REGISTRY_TOKEN.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_018n5ffHCn5QUjpDtuWTk3fh

.gitea/workflows/ci.yml

@@ -90,26 +90,26 @@ jobs:
           done
       - name: Upload plugin artifact to Gitea package registry
         env:
-          GITEA_TOKEN: ${{ secrets.GITEA_TOKEN }}
+          PKG_REGISTRY_TOKEN: ${{ secrets.PKG_REGISTRY_TOKEN }}
           BASE: ${{ github.server_url }}/api/packages/${{ github.repository_owner }}/generic/${{ env.PLUGIN_ID }}
         run: |
           if [[ "$GITHUB_REF" == refs/tags/v* ]]; then dirs="${GITHUB_REF_NAME#v}"; else dirs="main sha-${GITHUB_SHA::7}"; fi
           # Generic packages are immutable per version: delete first (ignored if absent) so
           # a re-run or a repeated push to a mutable version like "main" doesn't 409.
           for dir in $dirs; do
-            curl -fsS -X DELETE -H "Authorization: token $GITEA_TOKEN" "$BASE/$dir" || true
-            curl -fsS -X PUT -H "Authorization: token $GITEA_TOKEN" \
+            curl -fsS -X DELETE -H "Authorization: token $PKG_REGISTRY_TOKEN" "$BASE/$dir" || true
+            curl -fsS -X PUT -H "Authorization: token $PKG_REGISTRY_TOKEN" \
               --upload-file "dist/${PLUGIN_ID}.ndp" "$BASE/$dir/${PLUGIN_ID}.ndp"
-            curl -fsS -X PUT -H "Authorization: token $GITEA_TOKEN" \
+            curl -fsS -X PUT -H "Authorization: token $PKG_REGISTRY_TOKEN" \
               --upload-file "manifest.json" "$BASE/$dir/manifest.json"
             echo "uploaded $dir/${PLUGIN_ID}.ndp to Gitea packages"
           done
       - name: Link Gitea package to this repo
         env:
-          GITEA_TOKEN: ${{ secrets.GITEA_TOKEN }}
+          PKG_REGISTRY_TOKEN: ${{ secrets.PKG_REGISTRY_TOKEN }}
         run: |
           repo_name="${GITHUB_REPOSITORY#*/}"
-          curl -fsS -X POST -H "Authorization: token $GITEA_TOKEN" \
+          curl -fsS -X POST -H "Authorization: token $PKG_REGISTRY_TOKEN" \
             "${{ github.server_url }}/api/v1/packages/${{ github.repository_owner }}/generic/${{ env.PLUGIN_ID }}/-/link/$repo_name" \
             || echo "link skipped (already linked, or not yet supported)"