Reproduce sample 4 duplicate-port overcapacity

[ShiboSoftwareDev]

What this reproduces

The congested-port prepass can turn one graph opening into more physical lanes than the opening can carry.

This fixture uses the real dimensions of a sample 4 opening: it is 0.396 mm tall. With a 0.1 mm trace and 0.1 mm trace clearance, only two lanes fit. The current prepass creates seven lanes inside a fixed 0.05 mm band.

Snapshot

• Blue rectangles are the two real graph regions on either side of the opening.
• Red bands are the physical 0.1 mm traces.
• Orange bands show the required 0.2 mm center-to-center pitch.
• Black dots are the graph port centers.

The overlapping red/orange bands make the bug visible: the graph advertises seven routes through space that can carry only two.

Scope

This PR adds only the focused fixture and SVG snapshot. The fix is stacked separately so the same test naturally changes from the invalid seven-lane output to the legal two-lane output.

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Project	Deployment	Actions	Updated (UTC)
tiny-hypergraph	Ready	Preview	Aug 2, 2026 4:09am

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