bump: minor
type: feat
Namespaced spritesheet / atlas API (#81). Sprite loading was a bare `png_load("floor0.png")` — one file per 16x16 sprite, with no way to load one sheet and address a cell by grid coords or name. Adds a `Sprite.*` / `Assets.*` runtime (over the variable-size image loader, so a cell is a sub-rect of the kept image and is **not** restricted to the 16x16 sprite table): `Sprite.sheet(path, cellw, cellh)` -> handle, `Sprite.cell(sheet, col, row)` and `Sprite.cell_span(sheet, col, row, cols, rows)` -> id (a sprite may span more than one cell — a tall character, a wide object), `Sprite.define(name, …)` / `Sprite.named(name)` to name and look up a cell, `Sprite.draw` / `Sprite.draw_scaled` (through the camera / zoom / clip, like `Screen.sprite`), `Sprite.width` / `height`, and `Assets.image(path)` / `Assets.load` / `Assets.get(name)`. Spliced on demand; a program that uses neither compiles byte-identically. Example: `examples/library/atlas.ludic`.