#5008 Feature request: Remember last bridged asset value for easier repeat bridging

Problem

When testing the Union bridge protocol on testnet, I observed that when a user bridges assets, the input value is not retained for subsequent bridges. This means users must re-enter the same value if they wish to bridge multiple times with the same asset amount. This can create friction, especially for users who frequently bridge the same value.

Proposed Feature

Add a feature that remembers the last entered asset value for bridging. When a user completes a bridge transaction, the UI should retain the previously inputted value, so users can easily repeat the same bridge with the same amount. This would:

Reduce repetitive manual entry for frequent bridging
Improve user experience and efficiency
Make batch/multi-bridging more convenient

Usage Example

User initiates a bridge with value 'X'.
After completion, the input field retains value 'X'.
User can initiate another bridge with the same value without re-entering it.

Context

Requested during testnet by tester ID: ca1e76b3-f536-4880-9203-4d7f6ac7802d. This feature would be beneficial for both app.union.build and for the mainnet experience