feat: add MarketTickerTape component and include in Navbar

[EDOHWARES]

PR: Implement Live Market Ticker Tape

Summary

• Adds a persistent, animated market ticker tape to the app that displays live prices and 24h changes for top cryptocurrencies.
• Lightweight implementation with caching and graceful error handling.

Files changed

• Added: MarketTickerTape.tsx
• Modified: Navbar.tsx (imports and mounts the ticker so it is visible site-wide)

What it does

• Fetches top 20 cryptocurrencies by market cap from CoinGecko (USD) and displays:
  • Symbol (uppercase)
  • Current price (localized USD formatting)
  • 24h percentage change (color-coded: green for positive, red for negative)

Caching strategy

• Results cached in localStorage with a 5-minute TTL to minimize load and speed up page render.
• On fetch failure, attempts to show cached data and shows a friendly error message if nothing is available.

Auto-refresh

• Auto-refreshes data every 5 minutes (aligns with acceptance criteria).

Animation

• Smooth infinite horizontal scroll implemented by duplicating the item list and animating translateX.
• Desktop animation duration: 28s
• Mobile animation duration: 20s
• Keeps scroll smooth and responsive.

Pause-on-hover

• Hovering the ticker pauses animation immediately using CSS animation-play-state: paused.

Responsive behavior

• Condensed mobile view hides price text while keeping symbol and 24h change readable.

Accessibility & performance

• Uses aria-live="polite" to announce updates.
• Caching reduces network requests and minimizes initial load impact.

Notes / Caveats

• Source: CoinGecko public API (subject to rate limits).
• Consider using an API key or server-side proxy if heavy traffic is expected.
• Animation speed, duration, and styling can be tuned to match brand guidelines.
• The ticker is included via Navbar so it appears across waitlist and related pages.

How to test locally

1. Start the dev server:

npm install
npm run dev

2. Open site pages (home, waitlist, premium).

• The ticker should be fixed to the viewport bottom.

3. Verify:

• Symbols, prices, and 24h changes for the top ~20 coins.
• Positive changes appear green; negative changes appear red.
• Hovering the ticker pauses scrolling immediately.
• Prices update every 5 minutes (or refresh the page to observe a fresh fetch).
• If the network is unavailable, cached data (if present) is shown; otherwise a friendly error message is displayed.

4. Resize to mobile widths to verify the condensed layout.

Acceptance mapping

• Displays top 20 by market cap: ✅ (CoinGecko per_page=20)
• 24h changes update every 5 minutes: ✅ (fetch interval + cache TTL = 5 minutes)
• Smooth animation & pause-on-hover: ✅ (CSS keyframes + animation-play-state)
• Mobile condensed view: ✅ (price hidden on small screens)
• Error state: ✅ (friendly message with cached fallback)

Possible follow-ups

• Move fetching to an internal API route (server-side) to reduce dependency on CoinGecko rate limits.
• Tune animation speed or styling to better match product branding.
• Add unit tests and end-to-end tests for the component.

Closes #63

[EDOHWARES]

Pls approve workflow and merge PR