feat: commission status badge (open/closed/waitlist)

[KotaHusky]

Summary

Add a dynamic commission status badge to the homepage that clearly communicates whether photo commissions are currently open, closed, or on a waitlist. This is a standard UX pattern across furry artist hub pages and reduces inbound messages asking about availability.

Inspiration

Platforms like Beacons.ai and Furry Network surface commission availability as a first-class concept. Artists on FA, FurTrack, and DeviantArt all have some form of this — having it on the personal hub page gives visitors a definitive, always-current answer before they even click through to Ko-fi.

Proposed Behavior

• A small pill/badge component rendered near (or below) the "Photo Commission" HomepageButton
• Three states: Open (green), Closed (red/gray), Waitlist (yellow/amber)
• Status controlled by a single environment variable (e.g. NEXT_PUBLIC_COMMISSION_STATUS=open) so no code change is needed to toggle it
• Badge is visually distinct but not disruptive — subtle color + label

Acceptance Criteria

• CommissionStatusBadge component renders the correct color and label for each of the three states
• Status is driven by an env var (or a simple config value in app/config.ts)
• Badge is visible on both mobile and desktop without layout shift
• Default/missing env var falls back to "Closed" (safe default)
• Component has a unit test covering all three states