Backport of #6677 to rh-test branch.
## Changes
- Adds `preservedQueryTracker` to preserve template/source query params
during login/signup flows
- Resolves merge conflicts by keeping rh-test routing structure while
adding the fix
## Conflict Resolution
Kept rh-test branch structure:
- Import path: `./onboardingCloudRoutes` (not nested path)
- `PUBLIC_ROUTE_NAMES` and `isPublicRoute` at top level with
`/cloud/code` check
- Existing auth guard logic intact
Added from PR #6677:
- `installPreservedQueryTracker` with template/source keys
- New navigation utility files
## Testing
✅ Typecheck passes
✅ All new tests pass (20/20)
Fixes issue where template query params were being stripped during login
flows.
┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-6711-Backport-6677-fix-template-query-param-stripped-during-login-views-2ac6d73d36508115ad5fe2776fd93c7c)
by [Unito](https://www.unito.io)