feat: implement profile update form in SettingsPage

[wumibals]

Summary

Implements the profile update form in the Settings page as described in the issue.

Changes

• Updated: src/pages/dashboard/SettingsPage.jsx
  • Form with Full Name and Wallet Address fields using
    eact-hook-form
  • Pre-filled with current user data from Redux store (selectCurrentUser)
  • Stellar wallet address validated with Yup: must start with G and be exactly 56 characters
  • On valid submit, dispatches setCredentials to update the Redux store
  • Shows a success toast via
    eact-hot-toast on save
  • Inline error messages for invalid inputs

Acceptance Criteria Met

• Form is pre-filled with current user data
• Valid updates save and update the store
• Invalid wallet address shows a validation error

Closes #74

[ayshadogo]

LGTM

Thank you for your contribution 🤝