feat: port upstream OPDS improvements (PRs #1207, #1209)

Port two upstream PRs:

- PR #1207: Replace manual chunked download loop with
  HTTPClient::writeToStream via a FileWriteStream adapter, improving
  reliability for OPDS file downloads including chunked transfers.

- PR #1209: Add support for multiple OPDS servers with a new
  OpdsServerStore (JSON persistence with MAC-based password obfuscation),
  OpdsServerListActivity and OpdsSettingsActivity UIs, per-server
  credentials passed to HttpDownloader, web UI management endpoints,
  and migration from legacy single-server settings.

Made-with: Cursor

lib/I18n/I18nKeys.h

@@ -416,6 +416,12 @@ enum class StrId : uint16_t {
   STR_ACTION_FAILED,
   STR_BACK_TO_BEGINNING,
   STR_CLOSE_MENU,
+  STR_ADD_SERVER,
+  STR_SERVER_NAME,
+  STR_NO_SERVERS,
+  STR_DELETE_SERVER,
+  STR_DELETE_CONFIRM,
+  STR_OPDS_SERVERS,
   // Sentinel - must be last
   _COUNT
 };

lib/I18n/translations/czech.yaml

@@ -344,3 +344,9 @@ STR_INDEXING_STATUS_ICON: "Ikona stavového řádku"
 STR_SYNC_CLOCK: "Sync Clock"
 STR_TIME_SYNCED: "Time synced!"
 STR_AUTO_NTP_SYNC: "Auto Sync on Boot"
+STR_ADD_SERVER: "Přidat server"
+STR_SERVER_NAME: "Název serveru"
+STR_NO_SERVERS: "Žádné OPDS servery nejsou nakonfigurovány"
+STR_DELETE_SERVER: "Smazat server"
+STR_DELETE_CONFIRM: "Smazat tento server?"
+STR_OPDS_SERVERS: "OPDS servery"

lib/I18n/translations/english.yaml

@@ -380,3 +380,9 @@ STR_BOOK_REINDEXED: "Book reindexed"
 STR_ACTION_FAILED: "Action failed"
 STR_BACK_TO_BEGINNING: "Back to Beginning"
 STR_CLOSE_MENU: "Close Menu"
+STR_ADD_SERVER: "Add Server"
+STR_SERVER_NAME: "Server Name"
+STR_NO_SERVERS: "No OPDS servers configured"
+STR_DELETE_SERVER: "Delete Server"
+STR_DELETE_CONFIRM: "Delete this server?"
+STR_OPDS_SERVERS: "OPDS Servers"

lib/I18n/translations/french.yaml

@@ -344,3 +344,9 @@ STR_INDEXING_STATUS_ICON: "Icône barre d'état"
 STR_SYNC_CLOCK: "Sync Clock"
 STR_TIME_SYNCED: "Time synced!"
 STR_AUTO_NTP_SYNC: "Auto Sync on Boot"
+STR_ADD_SERVER: "Ajouter un serveur"
+STR_SERVER_NAME: "Nom du serveur"
+STR_NO_SERVERS: "Aucun serveur OPDS configuré"
+STR_DELETE_SERVER: "Supprimer le serveur"
+STR_DELETE_CONFIRM: "Supprimer ce serveur ?"
+STR_OPDS_SERVERS: "Serveurs OPDS"

lib/I18n/translations/german.yaml

@@ -344,3 +344,9 @@ STR_INDEXING_STATUS_ICON: "Statusleistensymbol"
 STR_SYNC_CLOCK: "Sync Clock"
 STR_TIME_SYNCED: "Time synced!"
 STR_AUTO_NTP_SYNC: "Auto Sync on Boot"
+STR_ADD_SERVER: "Server hinzufügen"
+STR_SERVER_NAME: "Servername"
+STR_NO_SERVERS: "Keine OPDS-Server konfiguriert"
+STR_DELETE_SERVER: "Server löschen"
+STR_DELETE_CONFIRM: "Diesen Server löschen?"
+STR_OPDS_SERVERS: "OPDS-Server"

lib/I18n/translations/portuguese.yaml

@@ -344,3 +344,9 @@ STR_INDEXING_STATUS_ICON: "Ícone da barra"
 STR_SYNC_CLOCK: "Sync Clock"
 STR_TIME_SYNCED: "Time synced!"
 STR_AUTO_NTP_SYNC: "Auto Sync on Boot"
+STR_ADD_SERVER: "Adicionar servidor"
+STR_SERVER_NAME: "Nome do servidor"
+STR_NO_SERVERS: "Nenhum servidor OPDS configurado"
+STR_DELETE_SERVER: "Excluir servidor"
+STR_DELETE_CONFIRM: "Excluir este servidor?"
+STR_OPDS_SERVERS: "Servidores OPDS"

lib/I18n/translations/romanian.yaml

@@ -319,3 +319,9 @@ STR_OPDS_SERVER_URL: "URL server OPDS"
 STR_SYNC_CLOCK: "Sync Clock"
 STR_TIME_SYNCED: "Time synced!"
 STR_AUTO_NTP_SYNC: "Auto Sync on Boot"
+STR_ADD_SERVER: "Adaugă server"
+STR_SERVER_NAME: "Numele serverului"
+STR_NO_SERVERS: "Niciun server OPDS configurat"
+STR_DELETE_SERVER: "Șterge serverul"
+STR_DELETE_CONFIRM: "Ștergi acest server?"
+STR_OPDS_SERVERS: "Servere OPDS"

lib/I18n/translations/russian.yaml

@@ -344,3 +344,9 @@ STR_INDEXING_STATUS_ICON: "Иконка в строке"
 STR_SYNC_CLOCK: "Sync Clock"
 STR_TIME_SYNCED: "Time synced!"
 STR_AUTO_NTP_SYNC: "Auto Sync on Boot"
+STR_ADD_SERVER: "Добавить сервер"
+STR_SERVER_NAME: "Имя сервера"
+STR_NO_SERVERS: "Нет настроенных серверов OPDS"
+STR_DELETE_SERVER: "Удалить сервер"
+STR_DELETE_CONFIRM: "Удалить этот сервер?"
+STR_OPDS_SERVERS: "Серверы OPDS"

lib/I18n/translations/spanish.yaml

@@ -344,3 +344,9 @@ STR_INDEXING_STATUS_ICON: "Icono barra estado"
 STR_SYNC_CLOCK: "Sync Clock"
 STR_TIME_SYNCED: "Time synced!"
 STR_AUTO_NTP_SYNC: "Auto Sync on Boot"
+STR_ADD_SERVER: "Añadir servidor"
+STR_SERVER_NAME: "Nombre del servidor"
+STR_NO_SERVERS: "No hay servidores OPDS configurados"
+STR_DELETE_SERVER: "Eliminar servidor"
+STR_DELETE_CONFIRM: "¿Eliminar este servidor?"
+STR_OPDS_SERVERS: "Servidores OPDS"

lib/I18n/translations/swedish.yaml

@@ -344,3 +344,9 @@ STR_INDEXING_STATUS_ICON: "Statusfältsikon"
 STR_SYNC_CLOCK: "Sync Clock"
 STR_TIME_SYNCED: "Time synced!"
 STR_AUTO_NTP_SYNC: "Auto Sync on Boot"
+STR_ADD_SERVER: "Lägg till server"
+STR_SERVER_NAME: "Servernamn"
+STR_NO_SERVERS: "Inga OPDS-servrar konfigurerade"
+STR_DELETE_SERVER: "Ta bort server"
+STR_DELETE_CONFIRM: "Ta bort denna server?"
+STR_OPDS_SERVERS: "OPDS-servrar"