Add ~/.claude.json to agent paths and use --bind-try

src/agents.rs

@@ -15,7 +15,8 @@ pub fn agent_rw_paths() -> Vec<PathBuf> {
             .map(PathBuf::from)
             .unwrap_or_else(|_| home.join(".codex")),
         home.join(".pi"),
+        home.join(".claude.json"),
     ];
 
-    candidates.into_iter().filter(|p| p.is_dir()).collect()
+    candidates.into_iter().filter(|p| p.exists()).collect()
 }