UI #22 — Build named accounts address book with save, load, and copy

[Tinna23]

Description

Users who regularly track the same Stellar accounts should be able to save those addresses with a human-readable label. Saved accounts can be loaded directly into the search or copied in one tap.

What To Build

src/hooks/useAddressBook.ts

• localStorage key: stellar-explain-address-book
• Each entry: { id, label: string, address: string, savedAt: ISO string }
• Maximum 50 saved accounts

src/components/addressbook/AddressBook.tsx

• Lists saved accounts: label (bold), truncated address, Copy, Load, Delete buttons
• Copy → copies full address with toast feedback
• Load → fills search bar and navigates to results

src/components/addressbook/SaveAddressButton.tsx

• Shown on the account result — a 'Save address' button
• Opens inline popover with address pre-filled and editable Label field (max 30 chars)
• On save: validates label non-empty, saves, shows toast: 'Saved as [label]'
• If already saved: button shows 'Saved ✓' with rename/delete option

Key Files

• src/hooks/useAddressBook.ts
• src/components/addressbook/AddressBook.tsx
• src/components/addressbook/SaveAddressButton.tsx

Acceptance Criteria

• Accounts can be saved with a label from the result view
• Saved accounts appear in the address book panel
• Load navigates and displays results
• Copy shows toast feedback
• Already-saved addresses show 'Saved ✓' state
• Label validation enforced

Complexity: Medium · 150 pts
Stage: S7 — Persistence (Wave 2)
Depends on: UI #7