Add mobile contact selection for send flow

[Brainoncrack]

Description

Difficulty: Hard

Type: Feature

Summary

Allow users to select a saved contact during the send flow.

Current Behaviour

Users may need to manually paste addresses even when contacts are saved.

Expected Behaviour

The send flow should support choosing a saved recipient from the address book.

Suggested Implementation

Add contact picker integration to the recipient step of the payment flow.

Files or Areas Likely Affected

app/
src/features/payments/
src/features/contacts/
src/components/

Acceptance Criteria

• Contact picker is available in send flow.
• Selected contact fills recipient address.
• Manual entry remains available.
• Empty contacts state is handled.
• Duplicate or invalid contact data is handled safely.

Additional Notes

This improves practical wallet UX.