refactor: process isolation support for node replacement API (#12298)

* refactor: process isolation support for node replacement API

- Move REGISTERED_NODE_REPLACEMENTS global to NodeReplaceManager instance state
- Add NodeReplacement class to ComfyAPI_latest with async register() method
- Deprecate module-level register_node_replacement() function
- Call register_replacements() from comfy_entrypoint()

This enables pyisolate compatibility where extensions run in separate
processes and communicate via RPC. The async API allows registration
calls to cross process boundaries.

Refs: TDD-002
Amp-Thread-ID: https://ampcode.com/threads/T-019c2b33-ac55-76a9-9c6b-0246a8625f21

* fix: remove whitespace and deprecation cruft

Amp-Thread-ID: https://ampcode.com/threads/T-019c2be8-0b34-747e-b1f7-20a1a1e6c9df

comfy_api/latest/_node_replace.py

@@ -1,13 +1,6 @@
 from __future__ import annotations
 
 from typing import Any
-import app.node_replace_manager
-
-def register_node_replacement(node_replace: NodeReplace):
-    """
-    Register node replacement.
-    """
-    app.node_replace_manager.register_node_replacement(node_replace)
 
 
 class NodeReplace:
@@ -30,9 +23,7 @@ class NodeReplace:
         self.output_mapping = output_mapping
 
     def as_dict(self):
-        """
-        Create serializable representation of the node replacement.
-        """
+        """Create serializable representation of the node replacement."""
         return {
             "new_node_id": self.new_node_id,
             "old_node_id": self.old_node_id,
@@ -58,9 +49,7 @@ class InputMap:
             }
 
     class OldId(_Assign):
-        """
-        Connect the input of the old node with given id to new node when replacing.
-        """
+        """Connect the input of the old node with given id to new node when replacing."""
         def __init__(self, old_id: str):
             super().__init__("old_id")
             self.old_id = old_id
@@ -71,9 +60,7 @@ class InputMap:
             }
 
     class SetValue(_Assign):
-        """
-        Use the given value for the input of the new node when replacing; assumes input is a widget.
-        """
+        """Use the given value for the input of the new node when replacing; assumes input is a widget."""
         def __init__(self, value: Any):
             super().__init__("set_value")
             self.value = value
@@ -95,9 +82,7 @@ class InputMap:
 
 
 class OutputMap:
-    """
-    Map outputs of node replacement via indexes, as that's how outputs are stored.
-    """
+    """Map outputs of node replacement via indexes, as that's how outputs are stored."""
     def __init__(self, new_idx: int, old_idx: int):
         self.new_idx = new_idx
         self.old_idx = old_idx