Launch `WatchtowerPlugin.watchtower.start_watching()` through
asyncio.run_coroutine_threadsafe instead of ensure_future to prevent the
following exception from happening when running python with
`PYTHONASYNCIODEBUG=1`.
```
20251103T165007.087746Z | ERROR | plugin.Plugins | cannot initialize plugin watchtower: Error loading watchtower plugin: RuntimeError('Non-thread-safe operation invoked on an event loop other than the current one')
Traceback (most recent call last):
File "/home/user/code/electrum-fork/electrum/plugin.py", line 629, in load_plugin_by_name
plugin = module.Plugin(self, self.config, name)
File "/home/user/code/electrum-fork/electrum/plugins/watchtower/watchtower.py", line 59, in __init__
asyncio.ensure_future(self.watchtower.start_watching())
~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/lib64/python3.14/asyncio/tasks.py", line 732, in ensure_future
return loop.create_task(coro_or_future)
~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^
File "/usr/lib64/python3.14/asyncio/base_events.py", line 468, in create_task
return self._task_factory(self, coro, **kwargs)
~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^
File "/home/user/code/electrum-fork/electrum/util.py", line 1773, in factory
task = asyncio.Task(coro, loop=loop_, **kwargs)
File "/usr/lib64/python3.14/asyncio/base_events.py", line 829, in call_soon
self._check_thread()
~~~~~~~~~~~~~~~~~~^^
File "/usr/lib64/python3.14/asyncio/base_events.py", line 866, in _check_thread
raise RuntimeError(
"Non-thread-safe operation invoked on an event loop other "
"than the current one")
RuntimeError: Non-thread-safe operation invoked on an event loop other than the current one
The above exception was the direct cause of the following exception:
Traceback (most recent call last):
File "/home/user/code/electrum-fork/electrum/plugin.py", line 184, in load_plugins
self.load_plugin_by_name(name)
~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^
File "/home/user/code/electrum-fork/electrum/plugin.py", line 631, in load_plugin_by_name
raise Exception(f"Error loading {name} plugin: {repr(e)}") from e
Exception: Error loading watchtower plugin: RuntimeError('Non-thread-safe operation invoked on an event loop other than the current one')
```
and restore ability to have different internal ConfigVar name and user-visible "key"
(Keys are hard to change as that breaks compat, but it is nice to be able to change
the internal var name, to reorganise stuff sometimes. After new ConfigVars are added,
sometimes we get better insight into how the older ones should have been named.)
follow-up https://github.com/spesmilo/electrum/pull/9648
running a watchtower requires to be able to run a daemon with the
watchtower plugin enabled. If users succeed at doing that, we
can expect them to be able to configure theclient using the
command line.
(that would not work with QML, though. maybe QML could use an
advanced config editor)
