Bump to 0.9.4

- SessionTimelineChart: adds explicit gap between the tooltip's device
  label and its value via a custom formatter, instead of relying on
  justify-between's leftover-space spacing, which collapsed to zero in
  the narrow single-item tooltip

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01BuWtppPBizG2NQRa31FCRa

package.json

@@ -1,6 +1,6 @@
 {
   "name": "sexy",
-  "version": "0.9.3",
+  "version": "0.9.4",
   "private": true,
   "scripts": {
     "dev": "next dev",