Controller v0.7.2: notification preferences sync to hub

- SyncPreferences() method on Notifier: POST to hub /api/v1/preferences
- IsEnabled() getter for hub connectivity check
- settingsNotificationsHandler: sync to hub after local save (3 flash message variants)
- Startup sync: non-blocking goroutine pushes prefs to hub on boot (DB rebuild recovery)
- Updated CONTEXT.md, README.md with v0.7.2 changes

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

controller/internal/notify/notifier.go

@@ -4,6 +4,7 @@ import (
 	"bytes"
 	"encoding/json"
 	"fmt"
+	"io"
 	"log"
 	"net/http"
 	"sync"
@@ -51,6 +52,60 @@ func New(hubURL, apiKey, customerID string, sett *settings.Settings, logger *log
 	}
 }
 
+// IsEnabled returns whether the notifier has a configured hub connection.
+func (n *Notifier) IsEnabled() bool {
+	return n.enabled
+}
+
+// preferencesRequest is the JSON payload sent to the hub preferences endpoint.
+type preferencesRequest struct {
+	CustomerID    string   `json:"customer_id"`
+	Email         string   `json:"email"`
+	EnabledEvents []string `json:"enabled_events"`
+}
+
+// SyncPreferences pushes the current notification preferences to the hub.
+// Called after the user saves notification settings on the settings page.
+// Synchronous — returns error for the handler to display to the user.
+func (n *Notifier) SyncPreferences(email string, enabledEvents []string) error {
+	if !n.enabled {
+		return fmt.Errorf("hub nem konfigurált")
+	}
+
+	payload := preferencesRequest{
+		CustomerID:    n.customerID,
+		Email:         email,
+		EnabledEvents: enabledEvents,
+	}
+
+	jsonData, err := json.Marshal(payload)
+	if err != nil {
+		return fmt.Errorf("marshal: %w", err)
+	}
+
+	url := n.hubURL + "/api/v1/preferences"
+	req, err := http.NewRequest("POST", url, bytes.NewReader(jsonData))
+	if err != nil {
+		return fmt.Errorf("request: %w", err)
+	}
+	req.Header.Set("Authorization", "Bearer "+n.apiKey)
+	req.Header.Set("Content-Type", "application/json")
+
+	resp, err := n.httpClient.Do(req)
+	if err != nil {
+		return fmt.Errorf("hub elérhetetlen: %w", err)
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode >= 400 {
+		body, _ := io.ReadAll(io.LimitReader(resp.Body, 512))
+		return fmt.Errorf("hub hiba (%d): %s", resp.StatusCode, string(body))
+	}
+
+	n.logger.Printf("[INFO] Notification preferences synced to hub: email=%s, events=%v", email, enabledEvents)
+	return nil
+}
+
 // notifyRequest is the JSON payload sent to the hub.
 type notifyRequest struct {
 	CustomerID string `json:"customer_id"`