feat: Immich API client with album, asset, and download support

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

src/immich_client.h

@@ -0,0 +1,41 @@
+#pragma once
+
+#include <Arduino.h>
+#include <vector>
+#include "settings.h"
+
+struct AlbumInfo {
+    String id;
+    String title;
+    int assetCount;
+};
+
+struct AssetInfo {
+    String id;
+    String originalFileName;
+    String dateTime;
+    String city;
+    String camera;
+    bool isFavorite;
+    bool isPortrait;
+    std::vector<String> people;
+};
+
+class ImmichClient {
+public:
+    void begin(const String& baseUrl, const String& apiKey);
+    std::vector<AlbumInfo> fetchAlbums();
+    std::vector<String> fetchAlbumAssetIds(const String& albumId);
+    std::vector<String> fetchFavoriteAssetIds();
+    AssetInfo fetchAssetInfo(const String& assetId);
+    bool downloadAsset(const String& assetId, ImageQuality quality,
+                       uint8_t** outBuffer, size_t* outSize);
+
+private:
+    String _baseUrl;
+    String _apiKey;
+
+    String buildUrl(const String& path);
+    String httpGet(const String& url);
+    bool httpGetBinary(const String& url, uint8_t** outBuffer, size_t* outSize);
+};