feat: photo queue manager with cycling modes and favorites weighting

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

src/photo_queue.h

@@ -0,0 +1,32 @@
+#pragma once
+
+#include <Arduino.h>
+#include <vector>
+#include "settings.h"
+
+class ImmichClient;
+
+class PhotoQueue {
+public:
+    void begin(ImmichClient& client, SettingsManager& settings);
+    bool sync();
+    String next();
+    String random();
+    String current();
+    size_t size();
+    bool needsResync();
+    String findPortraitPair(size_t startIndex);
+
+private:
+    ImmichClient* _client = nullptr;
+    SettingsManager* _settings = nullptr;
+
+    std::vector<String> _queue;
+    size_t _cursor = 0;
+    unsigned long _lastSyncTime = 0;
+
+    void shuffle();
+    void sortChronological(bool reverse);
+    void applyFavoritesWeighting();
+    std::vector<String> getSelectedAlbumIds();
+};