[Feature]: Show yearly savings badge on pricing page toggle

[akshatsinghai6682-sketch]

Current Behavior

On the pricing page (layer5.io/pricing), when users switch from Monthly to Yearly billing, the prices update but there is no visual indicator showing how much users save by choosing the yearly plan.

Monthly price: $16/user/month = $192/year
Yearly price: $164/user/year

Users have no way to quickly understand the savings without manually calculating the difference.

Desired Behavior

When the Yearly toggle is selected, display a savings badge or label showing the discount percentage or amount saved.

For example:

• A "Save 15%" badge on the Yearly toggle button
• Or "2 months free" text next to the yearly price
• Similar to how GitHub, Notion, and Linear display yearly savings

Screenshots / Mockups

Current state — no savings indicator on yearly toggle:
https://layer5.io/pricing

Reference: GitHub and Notion pricing pages show "Save X%" badge on yearly toggle to help users understand the value of annual billing.

Implementation

• Update the Monthly/Yearly toggle in src/sections/Pricing/index.js
• Add a savings badge/label next to the Yearly button
• Calculate savings percentage dynamically from plan data in src/sections/Pricing/generatePlans.js
• Style the badge consistently with existing pricing page design in src/sections/Pricing/pricing.style.js

Acceptance Tests

• Savings badge is visible when Yearly toggle is selected
• Badge shows correct savings percentage or amount saved
• Badge disappears or changes when Monthly toggle is selected
• Works correctly on mobile and desktop screen sizes
• Consistent with existing site design and theme (dark/light mode)

[akshatsinghai6682-sketch]

I'd like to work on this issue. I'm a React/JavaScript frontend developer and will submit a PR soon. plz assign this issue to me thanks!