Add Rune Lillesveen to regrets list

Author: lilles

planning/redmond-2026/index.md

@@ -117,3 +117,4 @@ Please list your availability in California time (morning/afternoon/all or speci
 | --- | --- |
 | Anders Hartvoll Ruud | Google |
 | Luke Warlow | Igalia |
+| Rune Lillesveen | Google |