Add the Config view: edit and save the settings, applied without a restart

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

internal/sabnzbd/sabnzbd.go

@@ -11,16 +11,26 @@ import (
 	"net/url"
 	"strconv"
 	"strings"
+	"sync"
 	"time"
 )
 
 // Client talks to a SABnzbd instance.
 type Client struct {
+	mu      sync.RWMutex // guards baseURL and apiKey, which Reconfigure can change
 	baseURL string
 	apiKey  string
 	http    *http.Client
 }
 
+// Reconfigure points the client at another instance or key.
+func (c *Client) Reconfigure(baseURL, apiKey string) {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	c.baseURL = strings.TrimRight(baseURL, "/")
+	c.apiKey = apiKey
+}
+
 // NewClient returns a client for the instance at baseURL.
 func NewClient(baseURL, apiKey string) *Client {
 	return &Client{
@@ -159,9 +169,12 @@ func boolParam(b bool) string {
 // {"status": false, "error": "..."}, which is turned into an error here.
 func (c *Client) call(ctx context.Context, params url.Values, out any) error {
 	params.Set("output", "json")
-	params.Set("apikey", c.apiKey)
+	c.mu.RLock()
+	baseURL, apiKey := c.baseURL, c.apiKey
+	c.mu.RUnlock()
+	params.Set("apikey", apiKey)
 
-	req, err := http.NewRequestWithContext(ctx, http.MethodGet, c.baseURL+"/api?"+params.Encode(), nil)
+	req, err := http.NewRequestWithContext(ctx, http.MethodGet, baseURL+"/api?"+params.Encode(), nil)
 	if err != nil {
 		return stripURL(err)
 	}