Add persistent conversations and update checks

prompts/roles/action.md

@@ -12,6 +12,9 @@ Available tools:
   Args: {"path": "."}
 - search_files: search text inside files in the current workspace.
   Args: {"query": "text to find", "path": ".", "glob": "*.py"}
+- os_update_check: check available operating system package updates without
+  refreshing package manager caches and without sudo.
+  Args: {}
 - shell_exec_safe: run a safe allowlisted shell command in the current workspace.
   Args: {"command": "pwd"}
 
@@ -21,3 +24,6 @@ follow-up information. Return actions=[] when the observations are sufficient
 for the thinker to answer.
 Use only the listed tools. Keep actions minimal and directly tied to the user's
 request. Do not invent tool names.
+For user requests like "check updates in the system", use os_update_check.
+Do not use apt update, apt-get update, sudo, su, or package installation commands
+for update checks.