feat: add OPDS server reordering with sortOrder field and numeric stepper

Servers are sorted by a persistent sortOrder field (ties broken
alphabetically). On-device editing uses a new NumericStepperActivity
with side buttons for ±1 and face buttons for ±10. The web UI gets
up/down arrow buttons and a POST /api/opds/reorder endpoint.

Made-with: Cursor

lib/I18n/I18nKeys.h

@@ -426,6 +426,7 @@ enum class StrId : uint16_t {
   STR_SAVE_HERE,
   STR_SELECT_FOLDER,
   STR_DOWNLOAD_PATH,
+  STR_POSITION,
   // Sentinel - must be last
   _COUNT
 };

lib/I18n/translations/czech.yaml

@@ -353,3 +353,4 @@ STR_OPDS_SERVERS: "OPDS servery"
 STR_SAVE_HERE: "Uložit zde"
 STR_SELECT_FOLDER: "Vybrat složku"
 STR_DOWNLOAD_PATH: "Cesta ke stažení"
+STR_POSITION: "Pozice"

lib/I18n/translations/english.yaml

@@ -390,3 +390,4 @@ STR_OPDS_SERVERS: "OPDS Servers"
 STR_SAVE_HERE: "Save Here"
 STR_SELECT_FOLDER: "Select Folder"
 STR_DOWNLOAD_PATH: "Download Path"
+STR_POSITION: "Position"

lib/I18n/translations/french.yaml

@@ -353,3 +353,4 @@ STR_OPDS_SERVERS: "Serveurs OPDS"
 STR_SAVE_HERE: "Enregistrer ici"
 STR_SELECT_FOLDER: "Sélectionner un dossier"
 STR_DOWNLOAD_PATH: "Chemin de téléchargement"
+STR_POSITION: "Position"

lib/I18n/translations/german.yaml

@@ -353,3 +353,4 @@ STR_OPDS_SERVERS: "OPDS-Server"
 STR_SAVE_HERE: "Hier speichern"
 STR_SELECT_FOLDER: "Ordner auswählen"
 STR_DOWNLOAD_PATH: "Download-Pfad"
+STR_POSITION: "Position"

lib/I18n/translations/portuguese.yaml

@@ -353,3 +353,4 @@ STR_OPDS_SERVERS: "Servidores OPDS"
 STR_SAVE_HERE: "Salvar aqui"
 STR_SELECT_FOLDER: "Selecionar pasta"
 STR_DOWNLOAD_PATH: "Caminho de download"
+STR_POSITION: "Posição"

lib/I18n/translations/romanian.yaml

@@ -328,3 +328,4 @@ STR_OPDS_SERVERS: "Servere OPDS"
 STR_SAVE_HERE: "Salvează aici"
 STR_SELECT_FOLDER: "Selectează dosar"
 STR_DOWNLOAD_PATH: "Cale descărcare"
+STR_POSITION: "Poziție"

lib/I18n/translations/russian.yaml

@@ -353,3 +353,4 @@ STR_OPDS_SERVERS: "Серверы OPDS"
 STR_SAVE_HERE: "Сохранить здесь"
 STR_SELECT_FOLDER: "Выбрать папку"
 STR_DOWNLOAD_PATH: "Путь загрузки"
+STR_POSITION: "Позиция"

lib/I18n/translations/spanish.yaml

@@ -353,3 +353,4 @@ STR_OPDS_SERVERS: "Servidores OPDS"
 STR_SAVE_HERE: "Guardar aquí"
 STR_SELECT_FOLDER: "Seleccionar carpeta"
 STR_DOWNLOAD_PATH: "Ruta de descarga"
+STR_POSITION: "Posición"

lib/I18n/translations/swedish.yaml

@@ -353,3 +353,4 @@ STR_OPDS_SERVERS: "OPDS-servrar"
 STR_SAVE_HERE: "Spara här"
 STR_SELECT_FOLDER: "Välj mapp"
 STR_DOWNLOAD_PATH: "Nedladdningssökväg"
+STR_POSITION: "Position"