Import upstream v0.16.24, stripped

Upstream commit: af37a234981722493b74623a983581691d2b70b6
Enterprise-only files removed or emptied: 63
Enterprise-only snippets removed: 118 in 50 files
Dangling module declarations removed: 5
Edits turning enterprise off: 25
Third-party code: 14 files, 0 not in THIRD-PARTY.md
Renamed identifiers: 62 in 18 files
Verification: clean

The same Enterprise footprint as v0.16.23. The build check fails only on
tests/src/directory/issuer.rs, unchanged since v0.16.23: it calls a helper
from upstream's Enterprise-only OIDC test, and tests issuer-based directory
routing, an Enterprise feature. main has never carried it.

crates/jmap/src/email/import.rs

@@ -18,7 +18,7 @@ use jmap_proto::{
     error::set::{SetError, SetErrorType},
     method::import::{ImportEmailRequest, ImportEmailResponse},
     object::email::EmailProperty,
-    request::MaybeInvalid,
+    request::reference::MaybeIdReference,
     types::state::State,
 };
 use mail_parser::{HeaderName, MessageParser};
@@ -128,7 +128,7 @@ impl EmailImport for Server {
                 }
             }
 
-            let MaybeInvalid::Value(blob_id) = email.blob_id else {
+            let MaybeIdReference::Id(blob_id) = email.blob_id else {
                 response.not_created.append(
                     id,
                     SetError::invalid_properties()