Submodule add or update

Before I update the submodule, make the change easy for reviewers. Show a concise diff that highlights only the submodule pointer and include a one‑paragraph justification: which release needs the pin, what API changes in the new submodule commit matter, and whether that commit introduces any new build steps. Flag any submodule updates that will require CI cache invalidation or credentials to fetch.

I updated libs/payment to point at commit 7a1d2c but CI now fails fetching the submodule. I don’t know whether this is a credentials issue, a private repo change, or a broken URL. What sequence of checks should I run locally and on CI to diagnose whether the failure is due to access rights, the remote URL, or the submodule commit being absent upstream?

Submodule updates repeatedly cause last‑minute release outages: broken fetches, missing tags, or incompatible API bumps. Where are we losing control — in dependency ownership, pinned commits, or CI fetch patterns — and which three habits would stop submodule changes from derailing releases?