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

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

internal/arr/client.go

@@ -11,16 +11,34 @@ import (
 	"net/http"
 	"net/url"
 	"strings"
+	"sync"
 	"time"
 )
 
 // Client is a minimal JSON client for the Radarr/Sonarr v3 API.
 type Client struct {
+	mu      sync.RWMutex // guards baseURL and apiKey, which Reconfigure can change
 	baseURL string
 	apiKey  string
 	http    *http.Client
 }
 
+// settings returns the current base URL and API key.
+func (c *Client) settings() (baseURL, apiKey string) {
+	c.mu.RLock()
+	defer c.mu.RUnlock()
+	return c.baseURL, c.apiKey
+}
+
+// Reconfigure points the client at another instance or key. Requests already
+// in flight are not affected.
+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 (without /api/v3).
 func NewClient(baseURL, apiKey string) *Client {
 	return &Client{
@@ -46,7 +64,8 @@ func (e *APIError) Error() string {
 // Do sends a request to /api/v3/<path>. body (if non-nil) is JSON-encoded and
 // 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 {
-	u := c.baseURL + "/api/v3/" + strings.TrimLeft(path, "/")
+	base, apiKey := c.settings()
+	u := base + "/api/v3/" + strings.TrimLeft(path, "/")
 	if len(query) > 0 {
 		u += "?" + query.Encode()
 	}
@@ -64,7 +83,7 @@ func (c *Client) Do(ctx context.Context, method, path string, query url.Values,
 	if err != nil {
 		return err
 	}
-	req.Header.Set("X-Api-Key", c.apiKey)
+	req.Header.Set("X-Api-Key", apiKey)
 	req.Header.Set("Accept", "application/json")
 	if body != nil {
 		req.Header.Set("Content-Type", "application/json")