Add integration tests for ingester insertion

Check if ingester is following the insertion data policy, and also other behaviors that we are allowing, such as insertion of data in inverted order (first test, then build, then checkout)

Start by locating the ingester insertion path and any existing integration tests. Check how the insertion data policy is enforced, then exercise the allowed inverted order—test, build, checkout—and confirm the expected insertion behavior is covered.

Written by the indexing model from the issue text.