Accept ADR 26 Validation Severity Levels (#1092)

* Accept ADR 26 Validation Severity Levels

* Update 026-validation-severity-levels.md

Author: JeroenDeDauw

docs/adr/026-validation-severity-levels.md

@@ -2,7 +2,7 @@
 
 Date: 2026-07-07
 
-Status: Draft
+Status: Accepted (2026-07-19)
 
 ## Context