conformance: create everything-client with basic scenarios and configure GitHub action to run it

- implement all non-auth scenarios (client OAuth is not yet supported)
- sse-retry is also implemented, but failing due to a bug in the SDK
- configure client-conformance job in the conformance GitHub action
- create a client-conformance.sh script and rename conformance.sh to server-conformance.sh

.github/workflows/nightly.yml

@@ -32,5 +32,5 @@ jobs:
       uses: actions/setup-node@39370e3970a6d050c480ffad4ff0ed4d3fdee5af # v4.1.0
       with:
         node-version: "20"
-    - name: Run conformance tests
-      run: ./scripts/conformance.sh
+    - name: Run server conformance tests
+      run: ./scripts/server-conformance.sh