feat: add user send mail and sent box (#1122)

* 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

e2e/fixtures/wrangler.toml.e2e

@@ -20,6 +20,7 @@ ENABLE_USER_CREATE_EMAIL = true
 ENABLE_USER_DELETE_EMAIL = true
 ENABLE_AUTO_REPLY = true
 DEFAULT_SEND_BALANCE = 10
+NO_LIMIT_SEND_ROLE = "case-role"
 ENABLE_ADDRESS_PASSWORD = true
 DISABLE_ADMIN_PASSWORD_CHECK = true
 ADMIN_PASSWORDS = '["e2e-admin-pass"]'