Keep a later config flag when extra words are present.

A non-flag word no longer stops parsing, and a missing home directory refuses to create or rewrite a config instead of writing an empty log path.

Co-authored-by: Cursor <cursoragent@cursor.com>

app.go

@@ -2,6 +2,8 @@ package main
 
 import (
 	"context"
+	"fmt"
+	"io"
 
 	"gitea.neitzel.de/konrad/funknetz/audio"
 	"gitea.neitzel.de/konrad/funknetz/station"
@@ -51,3 +53,15 @@ func openStation(args []string) (*station.Station, error) {
 	}
 	return station.New(station.Options{ConfigPath: path})
 }
+
+// openStationReported opens the station from args. A flag or config failure is
+// one line on stderr and the returned error. The window is not opened.
+func openStationReported(args []string, stderr io.Writer) (*station.Station, error) {
+	st, err := openStation(args)
+	if err != nil {
+		// The returned error is the failure. A write error does not replace it.
+		_, _ = fmt.Fprintln(stderr, err.Error())
+		return nil, err
+	}
+	return st, nil
+}