Fork Stalwart WebUI v1.0.11 as INBUXA Admin

- One edition: whatever edition the server reports, nothing is hidden or
  disabled as Enterprise-only (accountStore.setAccountInfo).
- INBUXA branding: name, logo (mark plus a text-colored wordmark), favicon,
  page titles, setup wizard text, and ihasmail's palette in light and dark.
- Two-factor setup names INBUXA as the issuer and drops the image parameter
  that made authenticator apps fetch a logo from a third-party site.
- Runs apart from the server: the server address can be set at deploy time
  with <meta name="api-base-url">, and OAuth endpoints the server returns as
  relative paths are resolved against the server's address, not the page's.
  Verified end to end against a separate inbuxa-server.
- Upstream's release workflow moved to .github-upstream so it never runs.

Upstream's history contains no Enterprise-only code, so this is an ordinary
fork. upstream is a fetch-only remote.

.github/workflows/build.yml

@@ -1,74 +0,0 @@
-name: Build and Release
-
-on:
-  push:
-    tags:
-      - 'v*'
-
-permissions:
-  contents: write
-
-jobs:
-  build:
-    runs-on: ubuntu-latest
-
-    steps:
-      - uses: actions/checkout@v6
-
-      - uses: actions/setup-node@v6
-        with:
-          node-version: 22
-          cache: npm
-
-      - run: npm ci
-
-      - run: npm run typecheck
-
-      - run: npx eslint src/
-
-      - run: npx vitest run
-
-      - run: npm run build
-
-      - name: Create webui.zip
-        working-directory: dist
-        run: zip -r ../webui.zip .
-
-      - name: Build release body
-        run: |
-          awk '/^## \[/{c++} c==1' CHANGELOG.md > release_body.md
-
-      - name: Release
-        uses: softprops/action-gh-release@v3
-        with:
-          files: webui.zip
-          body_path: release_body.md
-          # Tag-push releases are created as drafts; the `publish` job un-drafts
-          # them only after the build succeeds, so watcher notifications don't
-          # fire on broken builds.
-          draft: true
-
-  publish:
-    name: Publish release
-    needs: [build]
-    runs-on: ubuntu-latest
-    permissions:
-      contents: write
-    steps:
-      - name: Un-draft release
-        env:
-          GH_TOKEN: ${{ github.token }}
-        run: gh release edit "${{ github.ref_name }}" --draft=false --latest --repo "${{ github.repository }}"
-
-  cleanup:
-    name: Cleanup failed release
-    needs: [build]
-    if: failure()
-    runs-on: ubuntu-latest
-    permissions:
-      contents: write
-    steps:
-      - name: Delete draft release and tag
-        env:
-          GH_TOKEN: ${{ github.token }}
-        run: gh release delete "${{ github.ref_name }}" --yes --cleanup-tag --repo "${{ github.repository }}" || true