Add Test Gitea Login step to verify credentials

- New step added to verify Gitea login during 'push' and 'manual' events.
- Includes 'exit 1' to fail the pipeline immediately after verification.

Co-authored-by: openhands <openhands@all-hands.dev>

.woodpecker/build.yaml

@@ -50,3 +50,17 @@ steps:
         from_secret: gitea_token
     depends_on:
       - Build for ${SHORT}
+
+  - name: Test Gitea Login
+    image: img.kie.rs/jjkiers/rust-crossbuild:rust1.79.0-zig0.11.0-zig
+    when:
+      - event: [manual, push]
+    environment:
+      GITEA_SERVER_URL: https://code.kiers.eu
+      GITEA_SERVER_TOKEN:
+        from_secret: gitea_token
+    commands:
+      - scripts/install_tea.sh linux-amd64 https://gitea.com/api/v1/repos/gitea/tea/releases/latest
+      - ./tea login add
+      - ./tea login ls
+      - exit 1