Implement YEC 2025 Takeover for Desktop Stable

Creating this ticket to have a parent ticket

Launch date for YEC 2025 is October 14.

Each year from ~mid-October through the end of December, the Tor Project runs its year-end fundraising campaign (aka "YEC"). This is the time during which we raise the most money per year from individual donors. A key strategy in this campaign is a branded takeover of about:tor (desktop + mobile) that includes the year-end campaign "mini brand," new assets, a fundraising message, and a donate button.

• Figma files for inspection: Desktop | about:tor
• Illustrations:
  • globe-chain-burst.svg
  • heart.svg
• Font:
  • Title: Jacquard 12
  • Copy: SF Pro/sans-serif system fonts
• Color:
  • Background panel: #1F0333
  • Title and paragraph text: #ffffff
  • Button text: #15141A
  • Button background: #B6E368
• Other:
  • Closing the banner is meant to persist until the next opening of about:tor
  • Metrics URL to come for donate button cc @smith @arturom
  • Last year's ticket for reference: YEC 2024 Takeover for Desktop Stable

cc/ @nicob @gaba @bella @morgan