docs: update CHANGELOG.md for v10.5.4

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

CHANGELOG.md

@@ -2,6 +2,12 @@
 
 All notable changes to claude-mem.
 
+## [v10.5.4] - 2026-03-09
+
+## Bug Fixes
+
+- **fix: restore modes to correct location** — All modes (`code`, code language variants, `email-investigation`) were erroneously moved from `plugin/modes/` to `plugin/hooks/modes/` during the v10.5.3 release, breaking mode loading. This patch restores them to `plugin/modes/` where they belong.
+
 ## [v10.5.3] - 2026-03-09
 
 ## What's New
@@ -1181,19 +1187,3 @@ Version 9.0.0 introduces the **Live Context System** - a major new capability th
 
 See PR #558 for complete details and diagnostic reports.
 
-## [v8.5.9] - 2026-01-04
-
-## What's New
-
-### Context Header Timestamp
-
-The context injection header now displays the current date and time, making it easier to understand when context was generated.
-
-**Example:** `[claude-mem] recent context, 2026-01-04 2:46am EST`
-
-This appears in both terminal (colored) output and markdown format, including empty state messages.
-
----
-
-**Full Changelog**: https://github.com/thedotmack/claude-mem/compare/v8.5.8...v8.5.9
-