Add NotMPC ordering tab and PringlePrints listing

[WilfordGrimley]

Summary

• Adds a third tab to the "Print!" export page (FinishedMyProject.tsx) for ordering through NotMPC.com, matching the MakePlayingCards tab's structure (intro line, 3-step BigOL/BigLI numbered list, closing line).
  • Steps were derived from a live read of notmpc.com's site copy, simplified into: export images, configure your order, upload & checkout.
  • Flagged with a TODO comment for manual verification since the flow was sourced by an automated fetch, not a manual walkthrough.
• Adds a single-line listing below the tabs linking to PringlePrints.
  • Reserved fixed height for this line in the existing height-budget calculations (OtherPrintShopsHeight constant) rather than relying on scroll — the inner tab-content scroll region has overscroll-behavior: none, which was silently hiding the line on tabs with content taller than the viewport until this was accounted for.

Test plan

• npx prettier@2.7.1 --check on all changed files
• npx tsc --noEmit — no errors
• npx eslint on changed files — no new issues
• Manually verified in a running dev server via Playwright screenshots: MPC, NotMPC, and PDF tabs all render correctly, and the new footer line is visible and reachable (not clipped) on every tab.

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