fix(#2313): validate GetAgentMeta target against path traversal

hive-c0re/src/socket_server/mod.rs

@@ -419,6 +419,17 @@ async fn handle_get_agent_meta(
     name: Option<&str>,
 ) -> hive_sh4re::Response {
     let target = name.unwrap_or(agent);
+    // `name` is agent-supplied and flows into filesystem reads below
+    // (`read_agent_status_live`, `read_agent_matrix_identities` →
+    // `agent_notes_dir(target)`), where a `../` component would traverse at
+    // the OS level. Validate it before any path is built. The `None` default
+    // (`target == agent`) is the caller's own authenticated name, already
+    // valid — but validating unconditionally is simplest and harmless.
+    if let Some(reason) = crate::dashboard::validate_agent_name(target) {
+        return hive_sh4re::Response::Err {
+            message: format!("get_agent_meta: invalid agent name {target:?}: {reason}"),
+        };
+    }
     let (status_text, status_set_at, running) =
         crate::container_view::read_agent_status_live(target).await;
     let (hive_name, swarm_name) = crate::container_view::hive_swarm_names();
@@ -430,6 +441,13 @@ async fn handle_get_agent_meta(
         status_set_at,
         hive_name,
         swarm_name,
+        // Matrix identities are public handles (`name` / `user_id`
+        // `@user:server` / `homeserver`) — the access token lives separately
+        // in the agent's `matrix-token` and is never part of this response.
+        // Peer visibility is intentional: it lets an agent verify/contact
+        // another on a public matrix instance. The `validate_agent_name` gate
+        // above is what closes the real vector here (path traversal via `../`
+        // in an agent-supplied name).
         matrix_accounts: read_agent_matrix_identities(target),
     }
 }