v0.3.0

• Add diagram template with a position: relative container — direct <div> children are position: absolute by default for free-form layouts.
• All slide templates now have position: relative on the slide inner container, allowing absolutely positioned overlays in any template.
• Add slide scripting: a fenced ```javascript ``` block at the end of presenter notes is extracted and executed in the browser after each slide renders. The script receives a slide object scoped to the slide body.
• Add Slide#find(selector) — a pure CSS selector query returning a SlideElements collection with no side effects.
• Add SlideElements#build(n, options) — shows the first n matched elements, hides the rest, and assigns view-transition-name for morph transition matching. Accepts group (name prefix) and effect (entry animation) options.
• Add build effects via view-transition-class: fade, fly-left, fly-right, fly-up, fly-down, scale. Requires Chromium 125+; degrades gracefully to instant appear in other browsers.
• Rename magic-move transition to morph.
• Italic text in presenter notes is styled in amber to distinguish stage directions from spoken words.
• Add transitions guide and animating slides guide to documentation.