First start: create the config file and open the Config view

Without a config file arr-tui refused to start. It now creates an empty
one (private, with its directory) and opens the Config view. A service
with neither address nor key is "not configured", which validation
allows: its client returns ErrNotConfigured without a request, its
indicator stays grey, it is logged once as information, and its lists
say so instead of showing errors.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_019reK4DUGYqDUjniWYJvwUW

cmd/arr-tui/main.go

@@ -2,8 +2,10 @@
 package main
 
 import (
+	"errors"
 	"flag"
 	"fmt"
+	"io/fs"
 	"os"
 
 	"git.stinnesbeck.com/nils/arr-tui/internal/config"
@@ -38,6 +40,13 @@ func run() error {
 		*path = p
 	}
 
+	// No config yet (first start): create an empty one, the Config view fills it in.
+	if _, err := os.Stat(*path); errors.Is(err, fs.ErrNotExist) {
+		if err := config.Create(*path); err != nil {
+			return err
+		}
+	}
+
 	cfg, warnings, err := config.Load(*path)
 	if err != nil {
 		return err