76030ea6

Author: lcnbr <im@lcnbr.ch>

Committer: Lucien Huber <im@lcnbr.ch>

extend linnest edge endpoints, momentum display, and partial layouts

Edges take per-endpoint anchor distances and fitted coil endpoints,
momentum visibility is controlled through edge data, map-style gains
particle-only rendering and manual endpoint shading, and partial layouts
can close the remaining graph below the pinned part. Clinnet behaviour
tests cover the new public Typst API. The old single-file xbox example no
longer matches the map-style API and is removed; standalone xbox documents
replace it in the next change.

Clinnet's Typst behaviour tests now fail rather than skip without Typst
0.15, the clinnet CI check provides it, and the large layout-and-drawing
test is split into focused tests over shared staging helpers. Running
them fixed stale fixtures: the momentum fixture pins its arrow offset and
label gap, the cross-section fixture expects layout-core's label
distances, label visibility compares parsed path geometry, and the gamma
style assertions compile with a workspace root.

Clinnet's runtime test sources add the documentation theme imported by the
portal edge style, the developer-note digests for the changed Nix ranges are
refreshed with no-impact attestations, and the portal and about SVGs are
regenerated for the pattern changes.