Source .env from beacon7 instead of Gitea secrets

TX_URL and TX_PASSWORD are read from ~/testsuite_tx_ui/.env on the
runner host rather than Gitea repo secrets, which aren't configured.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

.gitea/workflows/hw-ci.yaml

@@ -31,10 +31,8 @@ jobs:
           "
 
       - name: Run UI regression tests
-        env:
-          TX_URL: ${{ secrets.TX_URL }}
-          TX_PASSWORD: ${{ secrets.TX_PASSWORD }}
         run: |
           cd ~/testsuite_tx_ui
           git pull
+          set -a && source .env && set +a
           ~/.local/bin/poetry run pytest -v