bug: one unbreakable post title widens the blog listing grid at 320px #54

Describe the bug

/blog/ scrolls sideways at 320px. A single post title — Array.prototype.diff(meaCulpa), 30 characters with no spaces — sets a min-content width the grid column can't go below, so the whole column widens and every card in it overflows.

Two things combine:

• src/components/blog/BlogList.astro:12 — <ul class="grid md:grid-cols-2 lg:grid-cols-3 gap-8">. There's no base grid-cols-1, and grid items default to min-width: auto, so a track can be forced wider than its share by one item's content.
• src/components/generic/SummaryCard.astro:28 — <h3 class="poppins text-lg md:text-xl title-clamp">. .title-clamp sets overflow: hidden, which clips the title visually but doesn't reduce its intrinsic min-content width. There's no overflow-wrap/word-break, so the long token still pushes the layout.

The overflow: hidden is why this is easy to miss — the page scrolls sideways but the title looks fine.

Steps to Reproduce

pnpm run build && pnpm run preview

Open /blog/ at a 320px viewport and compare document.documentElement.scrollWidth against clientWidth:

Expected behavior

No horizontal scroll at 320px. A long unbroken title wraps or is clipped without widening its grid column.

Additional context

Found during an adversarial review of #51 and confirmed pre-existing, not caused by that PR. Proven by swapping BlogSummaryCard.astro back to origin/main (tags hidden on mobile, none of the new wrapping utilities), rebuilding, and re-measuring: identical 27px overflow, same single culprit card. Hiding the tags entirely doesn't fix it — it's title-driven, not tag-driven.

320px is the narrowest mainstream phone width (iPhone SE 1st gen, and Android split-screen). Worth deciding whether it's still in scope for this site before spending time here; nothing between 375px and 1280px is affected.

Likely fix is one line on each side: min-w-0 on the grid item (or grid-cols-[minmax(0,1fr)] on the ul), plus overflow-wrap: anywhere or break-words on .title-clamp. The grid half is the more general fix — it protects against any over-wide card content, not just this title. Worth re-checking /blog/tags/<tag>/ and the homepage recent-posts grid at the same time, since they render the same card.