Show Circuit JSON and Altium in round-trip snapshots

[techmannih]

Previously, the real-board round-trip snapshots rendered Altium on both sides, making conversion differences difficult to identify.

This PR updates the snapshots to show:

• Left: Circuit JSON render
• Right: Generated Altium render

It also updates the affected PCB, schematic, and multi-sheet snapshots for consistent visual comparison.

[chatgpt-codex-connector]

You have reached your Codex usage limits for code reviews. You can see your limits in the Codex usage dashboard.

[ShiboSoftwareDev]

don't add fall backs to element dimensions, if a dimension is missing don't render the element otherwise it may look correct when it's not

[techmannih]

Note: This normalization is only used to render the Circuit JSON side of the visual snapshots. The Altium-to-Circuit JSON converter currently emits some pads and holes using non-canonical field combinations that circuit-to-svg cannot render directly.

These are likely bugs in the Altium-to-Circuit JSON conversion and should eventually be fixed there. Until then, this helper maps valid dimensions to renderer-compatible shape variants. If any required dimension is missing or invalid, the element is skipped instead of using a fallback value that could make incorrect geometry appear valid.