fix: display Available amount after staking correctly

[impelcrypto]

Pull Request Summary

• fix: display Available amount after staking correctly

Check list

• contains breaking changes
• adds new feature
• modifies existing feature (bug fix or improvements)
• relies on other tasks
• documentation changes
• tested on mobile devices

This pull request makes the following changes:

Fixes

The fix now uses remainingLockedTokensInitial instead of the reactive remainingLockedTokens.value. This ensures that:

1. The initial locked tokens value is captured before any staking amount is entered (this happens in the watch at the bottom of this file)
2. When calculating availableToVoteDisplay, we use this fixed initial value
3. This prevents the double-counting issue where the staking amount was reducing both remainingLockedTokens and being subtracted again in the display calculation

Now when you enter a staking amount:

• The available balance will simply decrease by that amount
• The remaining locked tokens display will update correctly

=Before=

• The Available amount after staking should be 558 as the inputted amount is 100, but the result is 458, it decreased the amount twice.

=After=

[github-actions]

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