fix: resolve signature birthday cakes broken images and sync dynamic weight pricing logic

[moon-26k]

📌 Overview

This Pull Request fixes the broken image rendering issue and incorrect pricing calculations in the Signature Birthday Cakes section.

🛠️ Changes Made

1. Added Asset Resources: Locally downloaded and added missing high-quality .png assets for all birthday cake variations (pineapplecake.png, chocoholiccake.png, black-forest-cake.png, Cheesecake.png) inside the public/assets/ directory to replace the missing external URLs.
2. Fixed Asset Mapping: Rewrote window.BIRTHDAY_FALLBACKS and image reference handlers to target the correct local filename strings and extensions (.png).
3. Synced Dynamic Pricing: Enhanced window.setCakeWeight and window.calculateBdayPrice to ensure that switching between weights (0.5kg, 1.0kg, 1.5kg, 2.0kg) dynamically recalculates the exact price based on the individual flavor's base price configuration (e.g., ₹950 for Dutch Truffle, ₹675 for Pineapple).
4. Casing & State Safety: Wrapped identifiers in a robust string normalizer (toLowerCase().trim()) to prevent any silent breaks due to text case mismatches.

🚀 How to Test

1. Go to the Signature Birthday Cakes section.
2. Click on different flavors (Pineapple, Cheesecake, etc.) -> Verify images swap correctly without breaks.
3. Toggle between different weights -> Verify the price updates dynamically according to the rules.
4. Click Add to Cart -> Verify the correct image and price persist inside the cart overlay.

#Closes #256

[vercel]

@moon-26k is attempting to deploy a commit to the adithyansubramani1-1657's projects Team on Vercel.

A member of the Team first needs to authorize it.

[moon-26k]

Hi @adithyan-css, I have fixed the broken images and synced the dynamic weight pricing logic for birthday cakes. Could you please authorize the Vercel deployment check when you get a chance? Thank you!