First draft, `asyncio`-task, sync-pausing Bo

Mostly due to magic from @oremanj where we slap in a little bit of
`.from_asyncio`-type stuff to run a `trio`-task from `asyncio.Task`
code!

I'm not gonna go into tooo too much detail but basically the primary
thing needed was a way to (blocking-ly) invoke a `trio.lowlevel.Task`
from an `asyncio` one (which we now have with a new
`run_trio_task_in_future()` thanks to draft code from the aforementioned
jefe) which we now invoke from a dedicated aio case-branch inside
`.devx._debug.pause_from_sync()`. Further include a case inside
`DebugStatus.release()` to handle using the same func to set the
`repl_release: trio.Event` from the aio side when releasing the REPL on
exit cmds.

Prolly more refinements to come ;{o

tractor/to_asyncio.py

@@ -579,12 +579,14 @@ def run_trio_task_in_future(
     cancel_scope = trio.CancelScope()
     finished: bool = False
 
-    # Monkeypatch the returned future's cancel() method to forward
-    # cancellation to the Trio task
-    cancel_message = None
+    # monkey-patch the future's `.cancel()` meth to
+    # allow cancellation relay to `trio`-task.
+    cancel_message: str|None = None
     orig_cancel = result_future.cancel
 
-    def wrapped_cancel(msg=None):
+    def wrapped_cancel(
+        msg: str|None = None,
+    ):
         nonlocal cancel_message
         if finished:
             # We're being called back after the task completed
@@ -605,7 +607,6 @@ def run_trio_task_in_future(
         return True
 
     result_future.cancel = wrapped_cancel
-    # End of monkeypatching
 
     async def trio_task() -> None:
         nonlocal finished
@@ -625,8 +626,8 @@ def run_trio_task_in_future(
                 result_future.set_result(result)
 
         except BaseException as exc:
-            # The result future gets all the non-Cancelled
-            # exceptions.  Any Cancelled need to keep propagating
+            # the result future gets all the non-Cancelled
+            # exceptions. Any Cancelled need to keep propagating
             # out of this stack frame in order to reach the cancel
             # scope for which they're intended.
             cancelled: BaseException|None