Add convenience builders for agents + some tests (#672)

Add convenience builders for agents + some tests (smoke and otherwise)

Bonus: 
- updated the github actions to run the smoketests when sdk.ts changes
- fix some other internal examples to use 'runloop' instead of 'sdk' to match our other docs

Author: jrvb-rl

.github/workflows/sdk-coverage.yml

@@ -3,6 +3,7 @@ name: SDK Smoke Tests & Coverage Check
 on:
   pull_request:
     paths:
+      - 'src/sdk.ts'
       - 'src/sdk/**'
       - 'tests/smoketests/object-oriented/**'
   workflow_dispatch: