v0.168.1

Patch Changes

• #1355 207828aa Thanks @tenphi! - Board: document that it measures itself, and pin the no-paint-before-measurement guarantee with a test.

  Two behaviours were already true and nowhere written down, which is enough to make a consumer rebuild both: a board observes its own container and derives the column width from it, and it renders no widgets at all until it has a width. The second is what makes the first look unreliable — at width 0 a column works out negative, so a board that painted then would flash every widget at a nonsense size, and a consumer who saw that would reasonably conclude the board cannot size itself.

  The result is a recognisable workaround: measure the box yourself, feed it back in as width, and gate your own render on measured > 0 — a ResizeObserver and an extra DOM node reimplementing what the board already does, plus a guaranteed empty first frame from the redundant gate.

  No behaviour change. A new Sizing section says what width is actually for (SSR, tests, forced-size exports — not everyday use), and a browser test now fails if the gate is removed. It has to be a browser test: jsdom reports every box as 0, so the situation under test cannot arise there.