sessions : registre des sessions + commande am sessions (issue #5) - lifecycle agent/repl, reconciliation des sessions interrompues, compteur sessions_count, filtres agent/projet/statut, show avec extrait de log

src/cli.rs

@@ -98,6 +98,20 @@ pub enum Command {
         /// Agent name or alias (omit to show all installed agents)
         agent: Option<String>,
     },
+    /// List the sessions of every agent (and of the interactive shell)
+    Sessions {
+        /// Only sessions of this agent
+        agent: Option<String>,
+        /// Only sessions of this project
+        #[arg(long, value_name = "PROJECT")]
+        project: Option<String>,
+        /// Only sessions with this status (running, stopped, failed, interrupted)
+        #[arg(long, value_name = "STATUS")]
+        status: Option<String>,
+        /// Show one session in detail (summary + log excerpt)
+        #[arg(long, value_name = "ID")]
+        show: Option<String>,
+    },
     /// Install an agent and its dependencies
     Install {
         /// Agent name or alias