v0.2.28_fix

RELEASE-VALIDATION.txt

@@ -1,7 +1,7 @@
 RustBox 0.2.28 - final source validation
 
 0.2.28 scope:
-- correct reply recipients for own sent messages in threads, reader thread/single-message toggle, and stronger Polish legacy-encoding/mojibake repair, plus the 0.2.27 mail-list and appearance baseline
+- correct reply recipients for own sent messages in threads, Roundcube-style mailbox thread/flat list toggle (compact icon-button matching Select messages, with an icon reflecting the active mode), and stronger Polish legacy-encoding/mojibake repair, plus the 0.2.27 mail-list and appearance baseline
 
 0.2.25 scope:
 - filters: apply now on existing messages (`POST /api/filters/match`, IMAP UID SEARCH bounds + cache), exceptions, new conditions and actions, templates, missing-folder creation, "always move from this sender"
@@ -72,6 +72,7 @@ RustBox 0.2.28 - final source validation
 Completed in this environment:
 - offline release validator: scripts/validate-release-static.py (458/458 checks passed)
 - browser JavaScript assembled in manifest order passes `node --check`
+- mailbox thread grouping smoke test covers a three-message References chain, expand/collapse behavior and flat-mode fallback
 - reply-recipient helper smoke test covers own-account, alias and normal incoming-message replies
 - supplied legacy Polish `.eml` decodes to the expected ISO-8859-2 subject and UTF-8 quoted-printable body in an independent MIME parser check
 - all JSON files parse successfully