feat(icons): size the mark to Apple's proportions, assemble it from layer art

[keiver]

Sizing

Every centred surface used a hardcoded 0.6 of the shorter side, via an iconScale option no caller ever passed. And the scale sized the artboard, so a designer's own transparent margin shrank the mark again. Tomo TV's art fills 67.6% of its 1024 artboard, so the iOS mark landed at 0.6 × 0.676 = 40.6% of the icon against the ~80% Apple's grid calls for.

The icon is now normalised to the square its visible artwork occupies before scaling, so the number means "the mark covers N% of the canvas" whatever padding the source carries.

Flag	Default	Source
--ios-icon-scale	0.8	Apple's icon grid centres the primary shape at ~80% of the canvas, ~10% margin
--tv-icon-scale	0.75	tvOS wants a 10-15% safe margin per layer (a focused icon scales ~1.05-1.1x and its layers shift); 0.75 leaves 12.5% a side

Both settable per project via CLI, config file, or the plugin (iosIconScale / tvIconScale).

One content box is measured per run, from the flat icon, and applied to every surface and every parallax layer. Sharing one transform is what keeps the layers registered: normalising each layer to its own bounds would slide the front layer off the middle one. The splash logo is untouched, it already fills its square.

Assembly

--icon is now optional when every icon layer carries its own art. The flat icon is composited from that art back to front and used for the appiconset, Top Shelf, splash logo and icon.png. Tomo TV's icon.svg was byte-for-byte layer-middle.svg + layer-front.svg, a third file kept in sync by hand.

Verified

Against Tomo TV's real art, measured from the generated PNGs:

	Before	After	Target
iOS icon-1024	40.6%	80.0%	~80%
tvOS middle layer	40.6%	75.0%	70-80%

Front layer still registered inside the middle layer's body. 325 tests pass (8 new).

Heads up on the version label

Labelled version:minor: the CLI/config API is backward compatible, every existing flag still works. But the generated icons change proportions for every existing project, which is a visible output change. Relabel to version:major before merging if you'd rather signal that.

Merging publishes to npm via release.yml.

[github-actions]

Released as v1.5.0 and published to npm.