Import upstream v0.16.25, stripped

Upstream commit: 3f657330c0f49a015a3a372fb59669b5cccbca6d
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: 67 in 19 files
Verification: clean

The same Enterprise footprint as v0.16.24. The build check is clean
apart from the expected errors in the rebuilt-feature tests. A
bug-fix release: DKIM rotation, IMAP failed-login answers, DNSBL
multi-code scoring and negative TTLs, Pyzor on short messages, queue
quotas with an empty match, RocksDB info-log rotation, and
Autodiscover schema handling.

crates/email/src/message/ingest.rs

@@ -20,7 +20,7 @@ use groupware::{
     scheduling::{ItipError, ItipMessages},
 };
 use mail_parser::{
-    DateTime, Header, HeaderName, HeaderValue, Message, MessageParser, MimeHeaders, PartType,
+    Header, HeaderName, HeaderValue, Message, MessageParser, MimeHeaders, PartType,
     parsers::fields::thread::thread_name,
 };
 use registry::{
@@ -924,11 +924,7 @@ impl EmailIngest for Server {
         span_id: u64,
     ) {
         if let Some(config) = &self.core.spam.classifier {
-            let mut dt = DateTime::from_timestamp(now() as i64);
-            dt.hour = 0;
-            dt.minute = 0;
-            dt.second = 0;
-            let until = dt.to_timestamp() as u64 + config.hold_samples_for;
+            let until = now() + config.hold_samples_for;
 
             let sample = SpamTrainingSample {
                 account_id: Some(Id::from(account_id)),