feat: migrate deprecated diagram to new yuml API

[chgeo]

The current diagram has a 'PLEASE MIGRATE' hint on it.

So:

• Migrate over to the new API
• Add a test for the diagram specifically.
• Regenerate tests

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Changes in detail:

URL migration (yuml.me → app.yuml.me v1)

• Base URL: https://yuml.me/diagram/class/ → https://app.yuml.me/diagram/v1/class/plain/
• Added .svg suffix required by v1
• Old style/direction params (;plain;dir:TB;scale:60) replaced by inline @direction LR DSL metadata and ?dir query param (which turned out not to work — only the inline DSL directive does)
• DSL is now encodeURIComponent-encoded before embedding in the URL (raw [, ], {, } caused 500 errors in v1)

Node disambiguation fix

• Old code used a literal %20 in the DSL to give entity set boxes a different name (Books ) from same-named entity type boxes (Books). v1 normalizes/trims whitespace in node names, collapsing them together.
• Replaced with U+200C (ZWNJ), an invisible zero-width character that v1 treats as part of the name, keeping the nodes distinct while rendering identically.

Legend

• @direction LR embedded in DSL for the horizontal layout
• Rendered via <img width="450"> for a smaller display size

ER diagram

• Rendered as a markdown linked image so clicking opens the full-size SVG

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Example from the test base:

test/lib/compile/data/example.openapi3.json

New:

Old

[daogrady]

First time I am consciously hearing of "yuml"...

thanks for the fix