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

internal/arr/client.go

@@ -48,6 +48,10 @@ func NewClient(baseURL, apiKey string) *Client {
 	}
 }
 
+// ErrNotConfigured is returned without a request while the client has no
+// address: the service is not set up.
+var ErrNotConfigured = errors.New("not configured: enter its address and API key in the Config view (F6)")
+
 // APIError is returned for non-2xx responses.
 type APIError struct {
 	Status  int
@@ -65,6 +69,9 @@ func (e *APIError) Error() string {
 // the response is decoded into out (if non-nil).
 func (c *Client) Do(ctx context.Context, method, path string, query url.Values, body, out any) error {
 	base, apiKey := c.settings()
+	if base == "" {
+		return ErrNotConfigured
+	}
 	u := base + "/api/v3/" + strings.TrimLeft(path, "/")
 	if len(query) > 0 {
 		u += "?" + query.Encode()

internal/arr/image.go

@@ -135,6 +135,9 @@ func (e *notImageError) Error() string {
 // their URL base in image paths, so it must not be added twice.
 func (c *Client) resolve(ref string) (string, error) {
 	baseURL, _ := c.settings()
+	if baseURL == "" {
+		return "", ErrNotConfigured
+	}
 	base, err := url.Parse(baseURL)
 	if err != nil {
 		return "", err