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**Related issue:** Resolves #
# Checklist for submitter
If some of the following don't apply, delete the relevant line.
Unreleased bug so no changes file
- [ ] Changes file added for user-visible changes in `changes/`,
`orbit/changes/` or `ee/fleetd-chrome/changes`.
See [Changes
files](https://github.com/fleetdm/fleet/blob/main/docs/Contributing/guides/committing-changes.md#changes-files)
for more information.
- [x] Input data is properly validated, `SELECT *` is avoided, SQL
injection is prevented (using placeholders for values in statements), JS
inline code is prevented especially for url redirects, and untrusted
data interpolated into shell scripts/commands is validated against shell
metacharacters.
## Testing
- [x] QA'd all new/changed functionality manually
<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit
* **Bug Fixes**
* Improved device and user registration reliability with clearer
validation and error handling.
* Added fallback username resolution when registration details are
incomplete.
* Registration now appropriately requests user interaction when
required.
* **Diagnostics**
* Added structured logging for network failures, invalid responses,
missing credentials, configuration errors, and registration outcomes.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->
Jordan Montgomery
4762dba089