core+gui: BBQR-only QR transfer, disable Audio when modem plugin unavailable

- Drop BALQR / BC-UR v1 / v2 wire formats, keep BBQR only (animated_qr,
  qrtransfer, dialogs); remove the settings "QR Code Size" selector and
  persist the export-dialog size choice instead.
- Disable the Audio transport radio button in the import/export dialogs
  when the audio_modem plugin (or its amodem dependency) is unavailable.
- Refresh translation catalogs (bal.pot, es_ES, it_IT).

bal/gui/qt/plugin.py

@@ -19,7 +19,6 @@ from electrum.plugin import hook
 from electrum.util import EventListener, event_listener
 from PyQt6.QtWidgets import QLayout
 
-from ...core.qrtransfer import CHUNK_PRESETS, preset_index_for_chunk_size
 from ...i18n import init_from_config
 from .common import (
     BalPlugin,
@@ -538,22 +537,6 @@ class Plugin(BalPlugin, EventListener):
         # users (BASIC and ADVANCED).
         heir_auto_rebuild = BalCheckBox(self.AUTO_REBUILD)
 
-        # QR Code Size selector (will transfer via QR). A 4-standard-size combo
-        # bound to the QR_CHUNK_SIZE config (payload budget in bytes per frame).
-        # Ordered low -> high so the user picks the resolution matching their
-        # camera. Visible to all users (BASIC and ADVANCED).
-        qr_size_combo = QComboBox()
-        # Labels marked for translation in common.QR_PRESET_LABELS.
-        qr_size_combo.addItems([_(label) for label, _budget in CHUNK_PRESETS])
-        qr_size_combo.setCurrentIndex(
-            preset_index_for_chunk_size(int(self.QR_CHUNK_SIZE.get()))
-        )
-
-        def on_qr_size_change(index):
-            self.QR_CHUNK_SIZE.set(CHUNK_PRESETS[index][1])
-
-        qr_size_combo.currentIndexChanged.connect(on_qr_size_change)
-
         # USER TYPE selector (SIMPLE / ADVANCED, global). A two-choice combo
         # (not a free-text field) bound to the USER_TYPE config:
         #   index 0 -> "BASIC"    -> stored value "basic"    (DEFAULT)
@@ -670,10 +653,6 @@ class Plugin(BalPlugin, EventListener):
                     widget.setCurrentIndex(
                         1 if str(cfg.default).lower() == "advanced" else 0
                     )
-                elif kind == "qr_size":
-                    widget.setCurrentIndex(
-                        preset_index_for_chunk_size(int(cfg.default))
-                    )
             btn.clicked.connect(reset)
             return btn
 
@@ -932,25 +911,6 @@ class Plugin(BalPlugin, EventListener):
         )
         grid.addWidget(reset_btn_auto_rebuild, 15, 3)
 
-        # "QR Code Size" row (always visible, BASIC + ADVANCED). Default QR
-        # size used when exporting a will via QR codes; changeable per export
-        # inside the export dialog itself.
-        lbl_qr_size = QLabel(_("QR Code Size"))
-        help_qr_size = HelpButton(_(
-            "Payload size of a single QR code when exporting a will via QR.\n\n"
-            "Larger QR codes hold more data (fewer shots) but are easier to "
-            "scan with a high-resolution camera; smaller QR codes scan fine "
-            "even with low-resolution cameras but require more shots.\n"
-            "The same selector is available inside the export dialog."
-        ))
-        grid.addWidget(lbl_qr_size, 16, 0)
-        grid.addWidget(qr_size_combo, 16, 1)
-        grid.addWidget(help_qr_size, 16, 2)
-        reset_btn_qr_size = _make_reset_btn(
-            self.QR_CHUNK_SIZE, qr_size_combo, "qr_size"
-        )
-        grid.addWidget(reset_btn_qr_size, 16, 3)
-
         # ----------------------------------------------------------------- #
         # Group C / C4b: "Reset" button that restores the dialog settings to  #
         # their factory defaults. It only resets the settings exposed by THIS #
@@ -984,7 +944,6 @@ class Plugin(BalPlugin, EventListener):
                 (self.HISTORY_LABEL, edit_history_label, "line"),
                 (self.REBUILD_ON_CLOSE, heir_rebuild_on_close, "check"),
                 (self.AUTO_REBUILD, heir_auto_rebuild, "check"),
-                (self.QR_CHUNK_SIZE, qr_size_combo, "qr_size"),
             ]
             for cfg, widget, kind in resets:
                 # Persist the default value back into the Electrum config.
@@ -1005,10 +964,6 @@ class Plugin(BalPlugin, EventListener):
                     widget.setCurrentIndex(
                         1 if str(cfg.default).lower() == "advanced" else 0
                     )
-                elif kind == "qr_size":
-                    widget.setCurrentIndex(
-                        preset_index_for_chunk_size(int(cfg.default))
-                    )
             # Re-sync the history-label field's enabled state after a reset: the
             # reset restores SAVE_HISTORY to its default, so the field must
             # follow the (default) checkbox state again.