Remove dead sentry.client.config.ts

[mazurroman]

Summary

• The entire `sentry.client.config.ts` was a single `/* ... */` block — the actual Sentry init has been commented out for a while.
• `@sentry/nextjs` is not in `package.json`, so the file could not be uncommented without re-introducing the dependency.
• Nothing in the repo imports or references the file. Deleting it is purely cleanup.

Test plan

• `grep sentry.client.config` returns no references outside the file itself
• `@sentry` does not appear in `package.json`