Log extensions.json loading (there or missing)

Spent time in a CRI and cause ended up being that the extensions.json file was missing in the deployment. Took way too long to figure out that was the issue. Log should be "loaded extensions.json" with another or same log that has contexts, or "tried to find extension.json and none was there" or something

No file or test is named in the issue. Locate the host entry point that loads extensions.json and review its existing logging, then add diagnostics distinguishing a successful load from a missing file and include relevant context. Done means deployment logs make the missing-file cause apparent.

Written by the indexing model from the issue text.