feat: settings manager with NVS persistence

Co-authored-by: Cursor <cursoragent@cursor.com>

src/main.cpp

@@ -1,6 +1,9 @@
 #include <Arduino.h>
 #include <M5Unified.h>
 #include "config.h"
+#include "settings.h"
+
+SettingsManager settingsManager;
 
 void setup() {
     auto cfg = M5.config();
@@ -15,9 +18,15 @@ void setup() {
     pinMode(PIN_SPK_EN, OUTPUT);
     digitalWrite(PIN_SPK_EN, LOW);
 
+    settingsManager.begin();
+    Settings settings = settingsManager.get();
+
+    Serial.printf("[main] Provisioned: %s\n", settingsManager.isProvisioned() ? "yes" : "no");
+    Serial.printf("[main] Immich URL: %s\n", settings.immich_url.c_str());
+    Serial.printf("[main] Interval: %d min\n", settings.interval_min);
     Serial.printf("[main] Free heap: %d, PSRAM: %d\n",
                   ESP.getFreeHeap(), ESP.getFreePsram());
-    Serial.println("[main] Boot complete (skeleton)");
+    Serial.println("[main] Boot complete");
 }
 
 void loop() {