feat(web): global deposit methods popup

[stackified]

Summary

• Adds a global, brand-themed deposit announcement modal that appears on site load across every page
• Centered modal with two-column layout (copy + AI-generated card/phone image), no auto-dismiss timer
• Closes via the ✕ symbol, "Close Window" link, backdrop click, or Escape
• Fixes basePath handling so images load correctly under the /RestroFX GitHub Pages deployment (popup image + the existing support-page hero)

Commits

• 9c3df8b feat(web): add global deposit methods popup
• 45f2a78 feat(web): redesign deposit popup as centered modal with branded image
• edcfd80 fix(web): resolve deposit popup image under GitHub Pages basePath
• dce7ede fix(web): load deposit support hero image under GitHub Pages basePath
• 9520438 chore(web): update deposit card images

Test plan

• Verify popup appears on homepage after load
• Verify popup appears on internal pages (e.g. /about, /platforms)
• Verify all close mechanisms work (X, Close Window, backdrop, Esc)
• Verify image loads (no broken placeholder) on the live /RestroFX/ site
• Verify support page hero image at /support/how-to-deposit-with-debit-cards renders
• Verify responsive layout on mobile (image stacks below copy)