Add MediaEval 2026 schedule to medico.md

Added schedule details for MediaEval 2026.

Author: cmihaigabriel

_editions/2026/tasks/medico.md

@@ -107,4 +107,11 @@ actively invited, and continuous support will be offered throughout the challeng
 * Michael A. Riegler, SimulaMet, Norway
 * Steven A. Hicks, SimulaMet, Norway
 
-
+##### MediaEval 2026 Schedule:
+
+* Registration for task participation opens: January 2026
+* Test data release: 1 March 2026
+* Runs due: 1 June 2026
+* Working notes papers due: 10 June 2026
+* MediaEval 2026 Workshop, Mon.-Tue. 15-16 June 2026, Amsterdam, Netherlands and Online, co-located with ACM ICMR 2026
+* Camera ready deadline: 30 June 2026