feat(nodes): restricts invocation context power

Creates a low-power `InvocationContext` with simplified methods and data.

See `invocation_context.py` for detailed comments.

invokeai/app/util/step_callback.py

@@ -1,12 +1,25 @@
+from typing import Protocol
+
 import torch
 from PIL import Image
 
+from invokeai.app.services.events.events_base import EventServiceBase
 from invokeai.app.services.invocation_processor.invocation_processor_common import CanceledException, ProgressImage
+from invokeai.app.services.invocation_queue.invocation_queue_base import InvocationQueueABC
+from invokeai.app.services.shared.invocation_context import InvocationContextData
 
 from ...backend.model_management.models import BaseModelType
 from ...backend.stable_diffusion import PipelineIntermediateState
 from ...backend.util.util import image_to_dataURL
-from ..invocations.baseinvocation import InvocationContext
+
+
+class StepCallback(Protocol):
+    def __call__(
+        self,
+        intermediate_state: PipelineIntermediateState,
+        base_model: BaseModelType,
+    ) -> None:
+        ...
 
 
 def sample_to_lowres_estimated_image(samples, latent_rgb_factors, smooth_matrix=None):
@@ -25,13 +38,13 @@ def sample_to_lowres_estimated_image(samples, latent_rgb_factors, smooth_matrix=
 
 
 def stable_diffusion_step_callback(
-    context: InvocationContext,
+    context_data: InvocationContextData,
     intermediate_state: PipelineIntermediateState,
-    node: dict,
-    source_node_id: str,
     base_model: BaseModelType,
-):
-    if context.services.queue.is_canceled(context.graph_execution_state_id):
+    invocation_queue: InvocationQueueABC,
+    events: EventServiceBase,
+) -> None:
+    if invocation_queue.is_canceled(context_data.session_id):
         raise CanceledException
 
     # Some schedulers report not only the noisy latents at the current timestep,
@@ -108,13 +121,13 @@ def stable_diffusion_step_callback(
 
     dataURL = image_to_dataURL(image, image_format="JPEG")
 
-    context.services.events.emit_generator_progress(
-        queue_id=context.queue_id,
-        queue_item_id=context.queue_item_id,
-        queue_batch_id=context.queue_batch_id,
-        graph_execution_state_id=context.graph_execution_state_id,
-        node=node,
-        source_node_id=source_node_id,
+    events.emit_generator_progress(
+        queue_id=context_data.queue_id,
+        queue_item_id=context_data.queue_item_id,
+        queue_batch_id=context_data.batch_id,
+        graph_execution_state_id=context_data.session_id,
+        node_id=context_data.invocation.id,
+        source_node_id=context_data.source_node_id,
         progress_image=ProgressImage(width=width, height=height, dataURL=dataURL),
         step=intermediate_state.step,
         order=intermediate_state.order,