fix(bal): black bar on cancelled invalidation + editable fee follows dates (v0.3.6)

Two GUI fixes bundled together (v0.3.6):

- Fix #10 (black bar): in dialogs.py on_success_phase1, the cancelled
  invalidation branch no longer calls the blocking self.wait(3)+self.close().
  wait() uses time.sleep() and runs in the GUI thread, freezing the UI so the
  'Building Will' dialog could not repaint the area it just resized, leaving a
  black rectangle at the bottom. It now shows 'Aborted' plus the existing
  non-blocking Close button (_add_close_button), consistent with the other
  end-of-flow branches.

- Fix #11 (editable fee): in widgets.py WillSettingsWidget.apply_editable_dates,
  the fee widget (baltx_fees) now follows the same 'Editable dates' setting as
  the locktime/threshold widgets (set_read_only(not editable_dates)) instead of
  being forced read-only. With the setting ticked, dates AND fee are editable
  outside the wizard; unticked, all three are read-only. Default stays OFF.

Version bumped 0.3.5 -> 0.3.6 (manifest.json, __init__.py, plugin_base.py,
VERSION). CHANGELOG: entries #10 and #11. ruff clean; full suite 239 passed.

bal/__init__.py

@@ -34,4 +34,4 @@ The plugin targets Electrum 4.7.2 (the last stable release exposing
 ``json_db.register_dict``) and PyQt6.
 """
 
-__version__ = "0.3.4"
+__version__ = "0.3.6"