docs: update CHANGELOG.md for v8.5.9

Author: thedotmack

CHANGELOG.md

@@ -2,6 +2,22 @@
 
 All notable changes to claude-mem.
 
+## [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
+
 ## [v8.5.8] - 2026-01-04
 
 ## Bug Fixes
@@ -1271,29 +1287,3 @@ npm run bug-report --help       # Show help
 
 **Full Changelog**: https://github.com/thedotmack/claude-mem/compare/v7.1.15...v7.2.0
 
-## [v7.1.15] - 2025-12-14
-
-## 🐛 Bug Fixes
-
-**Worker Service Initialization**
-- Fixed 404 error on `/api/context/inject` during worker startup
-- Route is now registered immediately instead of after database initialization
-- Prevents race condition on fresh installs and restarts
-- Added integration test for early context inject route access
-
-## Technical Details
-
-The context hook was failing with `Cannot GET /api/context/inject` because the route was registered only after database initialization completed. This created a race condition where the hook could attempt to access the endpoint before it existed.
-
-**Implementation:**
-- Added `initializationComplete` Promise to track async background initialization
-- Register `/api/context/inject` route immediately in `setupRoutes()`
-- Early handler blocks requests until initialization resolves (30s timeout)
-- Route handler duplicates logic from `SearchRoutes.handleContextInject` by design to prevent 404s
-
-**Testing:**
-- Added integration test verifying route registration and timeout handling
-
-Fixes #305
-Related: PR #310
-