Merge upstream v0.16.23

Five conflicts, resolved:

- crates/common/src/auth/authentication.rs: upstream's get_directory_for_token
  and JwtClaims replace extract_jwt_domain; the per-domain directory code
  (DIR-1, DIR-5 to DIR-7) is kept, and the token lookup routes through it.
  The release's one new Enterprise snippet was the body of
  get_directory_for_issuer, which stays returning None: a token naming no
  address gets the server default, as DIR-2 specifies and as v0.16.22 did.
- crates/common/src/manager/application.rs: upstream's rewrite of the tests,
  with the temp directory names renamed again, and the 5(a) notice the
  name-purge change should have added.
- crates/common/src/network/mta.rs: both sides' imports.
- crates/main/Cargo.toml: the AGPL-only license kept, version 0.16.23.
- Cargo.lock: upstream's, with the fork's crates added by Cargo.

crates/main/Cargo.toml

@@ -7,7 +7,7 @@ keywords = ["imap", "jmap", "smtp", "email", "mail", "webdav", "server"]
 categories = ["email"]
 # Upstream offers AGPL-3.0-only OR LicenseRef-SEL; INBUXA takes the AGPL only.
 license = "AGPL-3.0-only"
-version = "0.16.22"
+version = "0.16.23"
 edition = "2024"
 
 [[bin]]