fix: a wide table made the whole page scroll sideways on a phone

[fas89]

Found by looking at the rendered site in a browser, not at the HTML.

concepts/sovereignty.html carries a three-column comparison of the two sovereignty gates. At a 357px viewport it renders at its natural 595px, pushing the document to 619px — so the entire page scrolls horizontally, the classic mobile failure where body text drifts under your thumb as you scroll.

	before	after
document scrollWidth @ 357px	619	357
page scrolls horizontally	yes	no
wide table	overflows the page	309px box, 595px content, scrolls internally

Why it was only this page

Code blocks never had the problem: the theme gives pre an overflow-x: auto, which is why a 798px bash line sits happily inside a 307px column. Tables had no equivalent containment anywhere in the site. cli/validate.html is clean only because its widest table happens to fit.

So the fix is global rather than a tweak to one table: any table in the page body now scrolls inside its own box. display: block is what makes overflow-x apply at all — a display: table box ignores it — and width: fit-content keeps narrow tables at their natural size instead of stretching them to the column.

Two measurement traps, recorded because both nearly gave the wrong answer

getBoundingClientRect on clipped content reports the full width, not the visible width. Sorting elements by their right edge pointed straight at a code block sitting inside an already-scrollable pre — innocent. The guilty table was further down the list. The honest query is "widest element with no scrollable ancestor".

Reading a computed transform immediately after setting it returns the pre-transition value. That made the new skip link look as though it never revealed on focus — twice. It works: transition: transform .15s, and after settling it moves from -46px to 0 and back. No defect; my instrument was simply faster than the animation.

Also verified in the browser while there

• Light mode: zero contrast failures across hero, cards, body, links and sidebar — ratios 5.17 to 18.93 against a 4.5 requirement
• Both new hero cards render and read as intended
• The 0.15.0 release banner replaced the stale 0.12.0 block