update aichat config

aichat/.config/aichat/config.yaml

@@ -3,8 +3,9 @@
 # set API keys via environment variables, like CLAUDE_API_KEY
 # environment variables for aichat can be set at ~/.config/aichat/.env
 
-model: claude
+model: claude:claude-sonnet-4-5-20250929
 keybindings: vi
-prelude: role:cloudops
+repl_prelude: role:cloudops
 clients:
 - type: claude
+- type: gemini