* feat: add user send mail client
* fix: align user mail navigation
* fix: shorten address credential action
* test: cover user mail ownership boundaries
* fix: address user mail review feedback
* fix: disambiguate user mail e2e heading
* fix: minimize shared sent box changes
* refactor: isolate user send mail page
* refactor: reuse bound address lookup
* fix: clarify user sent box naming
* refactor: decouple user send API from roles
* fix: align user send mail behavior
* fix: align user send role and rate limits
* test: isolate user send rate limits
* test: initialize rate limit worker database
* refactor: simplify user send rate limit
* refactor: inline user send rate limit path
* refactor: simplify user send limiter key
* refactor: keep existing rate limit behavior
* style: simplify user send rate limit condition
* style: group user send rate limit condition
* fix: bind user role token to account
* fix: keep user sender selection available
