fix(cli): treat leading non-flag argument as target account for precise error feedback

bin/muse

@@ -39,15 +39,10 @@ show_usage() {
 ACCOUNT=""
 POSITIONAL=()
 
-# Pre-check if first argument is a valid account name (e.g. 'muse 646 ...')
-if [[ $# -gt 0 ]]; then
-    for acct in "${VALID_ACCOUNTS[@]}"; do
-        if [[ "$1" == "$acct" ]]; then
-            ACCOUNT="$1"
-            shift
-            break
-        fi
-    done
+# If first argument does not start with '-', treat it as the account candidate
+if [[ $# -gt 0 && "$1" != -* ]]; then
+    ACCOUNT="$1"
+    shift
 fi
 
 while [[ $# -gt 0 ]]; do