Port debug request ep to use `@context(pld_spec)`

Namely passing the `.__pld_spec__` directly to the
`lock_stdio_for_peer()` decorator B)

Also, allows dropping `apply_debug_pldec()` (which was a todo) and
removing a `lock_stdio_for_peer()` indent level.

tractor/devx/_debug.py

@@ -68,6 +68,7 @@ from trio import (
 )
 import tractor
 from tractor.log import get_logger
+from tractor._context import Context
 from tractor._state import (
     current_actor,
     is_root_process,
@@ -83,7 +84,6 @@ if TYPE_CHECKING:
     from trio.lowlevel import Task
     from threading import Thread
     from tractor._ipc import Channel
-    from tractor._context import Context
     from tractor._runtime import (
         Actor,
     )
@@ -529,7 +529,10 @@ class Lock:
             )
 
 
-@tractor.context
+@tractor.context(
+    # enable the locking msgspec
+    pld_spec=__pld_spec__,
+)
 async def lock_stdio_for_peer(
     ctx: Context,
     subactor_task_uid: tuple[str, int],
@@ -597,12 +600,6 @@ async def lock_stdio_for_peer(
         # scope despite the shielding we apply below.
         debug_lock_cs: CancelScope = ctx._scope
 
-        # TODO: use `.msg._ops.maybe_limit_plds()` here instead so we
-        # can merge into a single async with, with the
-        # `Lock.acquire_for_ctx()` enter below?
-        #
-        # enable the locking msgspec
-        with apply_debug_pldec():
         async with Lock.acquire_for_ctx(ctx=ctx):
             debug_lock_cs.shield = True
 
@@ -1037,48 +1034,6 @@ class PdbREPL(pdbp.Pdb):
         return None
 
 
-# TODO: prolly remove this and instead finally get our @context API
-# supporting a msg/pld-spec via type annots as per,
-# https://github.com/goodboy/tractor/issues/365
-@cm
-def apply_debug_pldec() -> _codec.MsgCodec:
-    '''
-    Apply the subactor TTY `Lock`-ing protocol's msgspec temporarily
-    (only in the current task).
-
-    '''
-    from tractor.msg import (
-        _ops as msgops,
-    )
-    cctx: Context = current_ipc_ctx()
-    rx: msgops.PldRx = cctx.pld_rx
-    orig_pldec: msgops.MsgDec = rx.pld_dec
-
-    try:
-        with msgops.limit_plds(
-            spec=__pld_spec__,
-        ) as debug_dec:
-            assert (
-                debug_dec
-                is
-                rx.pld_dec
-            )
-            log.runtime(
-                'Applied `.devx._debug` pld-spec\n\n'
-                f'{debug_dec}\n'
-            )
-            yield debug_dec
-
-    finally:
-        assert (
-            rx.pld_dec is orig_pldec
-        )
-        log.runtime(
-            'Reverted to previous pld-spec\n\n'
-            f'{orig_pldec}\n'
-        )
-
-
 async def request_root_stdio_lock(
     actor_uid: tuple[str, str],
     task_uid: tuple[str, int],
@@ -1147,6 +1102,7 @@ async def request_root_stdio_lock(
                     async with portal.open_context(
                         lock_stdio_for_peer,
                         subactor_task_uid=task_uid,
+
                         # NOTE: set it here in the locker request task bc it's
                         # possible for multiple such requests for the lock in any
                         # single sub-actor AND there will be a race between when the
@@ -1159,7 +1115,7 @@ async def request_root_stdio_lock(
                         # this IPC-ctx request task, NOT any other task(s)
                         # including the one that actually enters the REPL. This
                         # is oc desired bc ow the debugged task will msg-type-error.
-                        pld_spec=__pld_spec__,
+                        # pld_spec=__pld_spec__,
 
                     ) as (req_ctx, status):
 
@@ -2856,7 +2812,9 @@ def open_crash_handler(
 
 
 @cm
-def maybe_open_crash_handler(pdb: bool = False):
+def maybe_open_crash_handler(
+    pdb: bool = False,
+):
     '''
     Same as `open_crash_handler()` but with bool input flag
     to allow conditional handling.