Add static auto-layout graph visualization

[lgulich]

Summary

• Replace the old manual Matplotlib/NetworkX graph drawing path with a static layered auto-layout renderer.
• Emit both <graph_name>.svg and <graph_name>.png from leapp.compile_graph(visualize=True).
• Render graph inputs/outputs, node names, backend labels, port names, tensor shapes/dtypes, and semantic kind when available.
• Split the reusable graph model, layout, geometry, SVG, and PNG rendering code into a sibling leapp-visualization pip package.
• Keep visualization enabled by default: leapp now depends on leapp-visualization==0.5.2, resolved locally by uv from packages/leapp-visualization during development.
• Move visualization-only dependencies (fast-sugiyama, Pillow) into leapp-visualization.
• Update docs, examples, and tests for the new SVG+PNG visualization behavior.

Package layout

• packages/leapp-visualization/src/leapp_visualization/: generic visual graph dataclasses, layout, geometry, SVG renderer, PNG renderer, and render_graph(...).
• leapp/leapp_graph/visualization_adapter.py: LEAPP-specific adapter from LEAPP nodes/connections/tensor descriptors into leapp_visualization.VisualGraph.
• leapp/leapp_graph/graph_gui.py: compatibility wrapper used by compile_graph(visualize=True).

Example artifacts

Generated on this branch by leapp.compile_graph(visualize=True):

• SVG: graph_visualization_autolayout_example.svg
• PNG: graph_visualization_autolayout_example.png

GR00T Graph Example

Larger saved LEAPP export rendered with the same static auto-layout path:

• PNG: gr00t_unitree_g1_graph_visualization.png

Verification

• uv run pytest tests/unit_tests/test_graph_visualization_*.py tests/functional_tests/test_annotate.py::TestAnnotateTensor::test_annotate_traced_tensors_diamond_with_feedback tests/test_examples/test_getting_started.py::TestGettingStarted::test_getting_started_execution tests/test_examples/test_feedback_example.py::TestFeedbackExample::test_feedback_example_execution -q -> 38 passed, 4 warnings
• uv build packages/leapp-visualization && uv build -> built both distributions successfully

[frlai]

is there a way to make it so the python version isn't forced to be 3.11?
I think minimum we can get away with is 3.10. this is because gr00t requires 3.10

[lgulich]

this is tough. I added 3.11 because fast-sugiyama (the layout library) needs it. If we cannot use 3.10 then we have to write the layout library from scratch

[frlai]

do you know if gr00t requiring 3.10 is actually true? I think the public github still says requires 3.10 but at the same time it seems like you were able to run a test. If 3.10 is true we can make graphing optional depending on the python version the user is running? like before import add a try except. we can probably make this condition reflect in the pyproject too.