Add multisig address history to TUI

[0xbe1]

Summary

This PR adds multisig address history to the TUI, making it much easier to switch between frequently-used multisig accounts without having to re-type addresses.

Changes

Storage Layer (src/storage.ts)

• Added MultisigHistoryEntry type with network and address fields
• Extended SafelyStorage to include multisigHistory array
• Created MultisigHistory accessor with methods:
  • getAll() - retrieves all stored multisig addresses
  • getForNetwork(network) - filters by network
  • add(network, address) - adds new multisig with deduplication
  • remove(network, address) - removes specific entry
• History is stored per-network in ~/.safely/config.json

UI Layer (src/ui/HomeView.tsx)

• Updated multisig menu to display saved addresses and input field together
• Arrow keys navigate through history items and input field
• Input field shown as "New:" entry at bottom of list
• Automatically saves validated multisig addresses to history
• History updates when switching networks
• Unified UX without mode switching

User Experience

Before:

• Had to type full multisig address every time
• No way to quickly switch between multisigs

After:

▼ Multisig:
  ▶ 0x4dcae85f...ff5ee9 ✓
    0x9b831e42...77669d
    New: [text input]

• Navigate with arrow keys between saved addresses
• Press Enter to select
• Type in "New:" field to add another address
• Network-specific history

Test plan

• Build succeeds
• Test adding new multisig address
• Test selecting from history
• Test switching networks updates history
• Test address validation still works
• Test history persists across sessions

🤖 Generated with Claude Code