Article CTA Overhaul, Footer Mobile Responsiveness

Article CTA Overhaul

Replaced per-article markdown CTAs with a single consistent CTA section in the [slug].astro template. Full-width gradient background with soft launch messaging and early access positioning.

• Removed duplicate “Ready to Try It?” CTAs from all 11 Insights articles
• New CTA copy — “Early access for developers” with soft launch messaging, 90-day trial, and “Start free trial” / “Read the docs” buttons
• Full-width gradient — from-slate-50 to-slate-200 flows seamlessly into the dark footer
• Removed “Questions or feedback?” discuss box (redundant with contact page link in footer)

Footer Mobile Responsiveness

• Single-column stacking on mobile (grid-cols-1) with two columns from sm: breakpoint
• Larger tap targets — links scale to text-base with py-1.5 padding on mobile, reset to text-sm on desktop
• Heading size — bumped to text-base on mobile for better visual hierarchy
• Hidden spacer columns on mobile to prevent empty gaps in the grid