MCP Server Part 1: framework utilities and types

[KoolADE85]

Summary

For schema generation:

• Make Dash Component class compatible with Pydantic
• Move NumberType definition out from individual components into a generic place where the type can be introspected (and also made compatible with Pydantic)
• Add stronger type definitions for callbacks (CallbackDispatchBody, CallbackDispatchResponse)

Utilities

• Add framework utilities for traversing layouts and inspecting Dash components (dash/layout.py)
• Add pydantic>=2.10 to dependencies

Manual testing

There isn't any visible feature, but you can try out the layout traversal and pydantic type exposure by hand:

from dash import Dash, html, dcc
app = Dash(__name__)
app.layout = html.Div([
    html.Label("Name:", htmlFor="name-input"),
    " ",
    dcc.Input(id="name-input", value="World"),
    html.Div([html.Span(id="deep-child", children="deep text")], id="inner"),
], id="root")

with app.server.app_context():
    from dash.layout import traverse, find_component, extract_text
    for comp, ancestors in traverse(app.get_layout()):
        indent = "  " * len(ancestors)
        print(f"{indent}{type(comp).__name__} id={getattr(comp, 'id', None)}")

    from pydantic import TypeAdapter
    from dash.development.base_component import Component
    print(TypeAdapter(Component).json_schema())

[github-actions]

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This PR is exempt from requiring a linked issue due to its labels.