Rework Conf 2026 sponsor sizing for clearer tier hierarchy

[jeanlucaslima]

Closes #2403

Summary

The 2026 Sponsors section had inconsistent visual hierarchy: Gold and Silver logos rendered larger than Platinum because every non-Meta logo was forced into a fixed aspect-[3] box while Meta was constrained by aspect-video. Logos with internal SVG whitespace (Meta, airbnb) and logos with very different aspect ratios within the same tier (wide Apollo vs square ChilliCream) further compounded the imbalance.

This PR replaces the fixed-aspect approach with per-tier max-h / max-w envelopes plus optional per-logo overrides for cases where intrinsic aspect ratios make a single tier rule look unbalanced.

Changes

src/app/conf/2026/components/sponsors.tsx

• Tier sizing uses Tailwind max-h-* max-w-* per tier with mobile + desktop breakpoints. Logos render at their natural aspect via object-contain capped by the envelope.
• Added optional sizeOverride field on Sponsor so individual logos with extreme aspect ratios (square ChilliCream, stacked airbnb, small Grafast) can be tuned without raising the whole tier.
• Switched the row layout from a 2-column grid to flex with justify-center so single-logo tiers (Platinum, Community, Bronze) center on the section instead of sitting in the left grid column.
• Tier label is md:absolute on desktop so logos align to the section's true horizontal center, not centered relative to the post-label area.
• Meta <img> no longer needs the aspect-video wrapper; the cropped SVG handles its own sizing.

SVG asset cleanup

• Cropped internal whitespace from Meta.svg and Meta-dark.svg (viewBox="940 940 5100 1120").
• Aligned airbnb.svg width/height attributes with the cropped viewBox so the logo fills its envelope without internal padding.
• Added explicit width/height attributes to Chillicream.svg, airbnb.svg, Meta.svg, Meta-dark.svg so they have intrinsic dimensions when sized via max-h/max-w alone (previously these collapsed without the aspect-[3] wrapper).

Result

Visual hierarchy now reads Platinum > Gold > Silver/Community > Bronze at any viewport, and logos within a tier feel comparable in visual weight regardless of shape.

Test plan

• Open /conf/2026/#sponsors and confirm tier hierarchy reads correctly
• Verify all logos render in light and dark mode
• Check at 375px, 768px, 1280px, 1920px viewports
• Confirm hover state (subtle gray background) still appears on each logo tile

[vercel]

@jeanlucaslima is attempting to deploy a commit to the The GraphQL Foundation Team on Vercel.

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[jeanlucaslima]

Adding a before/after comparison:

[jeanlucaslima]

Focus was to give ChilliCream a visual equivalence because it is a more vertical logo