Refine edge attachment helper geometry extraction

[ibgreen]

Summary

• streamline the edge attachment helper by modularizing node geometry accessor construction and normalization helpers
• filter node style props when deriving geometry data so non-visual flags do not leak into stylesheet parsing
• retain edge layout adjustments by computing boundary intersections with simplified geometry resolution

Testing

• git commit (fails: Vitest pre-commit hook cannot resolve @deck.gl-community/template package entry)

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https://chatgpt.com/codex/tasks/task_e_6904bbb89a0c8328921afcee014a74b0