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/spam-filter/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "spam-filter"
-version = "0.16.24"
+version = "0.16.25"
 edition = "2024"
 
 [dependencies]