chore: bump agent to 3.5-net for the right-sized speed probe

The probe changed (4/2 MB once a day instead of 8/4 MB every 6h) after the
fleet was already on 3.4-net, so the version had to move for the rollout to
be trackable — identical version strings with different agent code is the
drift the install banner fix was meant to prevent.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

deploy_agent.sh

@@ -116,7 +116,7 @@ def get_cpu_temp():
         pass
     return None
 
-AGENT_VERSION = "3.4-net"
+AGENT_VERSION = "3.5-net"
 
 CLIENT_ID = "TEMPLATE_CLIENT_ID"
 CENTRAL_BASE = "TEMPLATE_CENTRAL_URL"