Node settings arrive as keyword arguments, not a params dict

A python node's settings are constants of its own function, so they are passed
the way its ports are: by name. The controller binds them to the compiled
function, the `params` field is gone from the worker and remote protocols, and
a setting sharing a port's name is reported as a node error rather than
shadowing it. The panel's scaffold follows suit and keeps the header in step
with both ports and settings.

The demo's `pace` moves from a flow input to a setting of the training node,
which is what it always was.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01NUb8YpL2s3gmN9WTACTt4q

backend/tests/flow/test_logs.py

@@ -4,6 +4,7 @@ import sys
 from typing import Any
 
 from app.flow import logs
+from app.flow.controller import with_settings
 from app.flow.messages import DType, MessageSpec
 from app.flow.nodes import Node
 from app.flow.pipeline import Pipeline
@@ -73,7 +74,7 @@ def test_a_failing_node_reports_its_traceback():
     namespace: dict[str, Any] = {}
     exec(
         compile(
-            'def process(params):\n    print("about to fail")\n'
+            'def process():\n    print("about to fail")\n'
             '    raise RuntimeError("boom")\n',
             "<node demo.broken>",
             "exec",
@@ -82,7 +83,11 @@ def test_a_failing_node_reports_its_traceback():
     )
 
     bus = RecordingBus()
-    run_with_capture([make_node("broken", namespace["process"])], bus)
+    # Wrapped the way the controller wraps it, so the settings a node declares
+    # arrive as keyword arguments and the frames match the real call.
+    run_with_capture(
+        [make_node("broken", with_settings(namespace["process"], {}))], bus
+    )
 
     captured = logs_of(bus)
     assert len(captured) == 1