feat: multisig UX improvements

[n13]

Summary

• Fix fee calculation to show proposer's balance (not multisig balance) and display specific "Insufficient Balance for Fee" error
• Replace "TO" row with "PROPOSER" showing full address + checkphrase; remove all abbreviated addresses from review screen
• Client-side fallback decoding of proposal amount/recipient from call_raw when indexer fails
• Change "APPROVED" pill to "SIGNED" to avoid confusion about overall proposal status
• Add tilde prefix to estimated expiry time; enforce minimum 24h expiry
• Silent refresh for open proposals (no visible loading swirl)
• Add "DONE" button to dismiss proposal detail sheet after signing

Test plan

• Create a multisig proposal and verify proposer balance and fee error display correctly
• Review screen shows full addresses and proposer row
• Existing proposal with indexer decode failure still shows amount and recipient
• Status pills show "SIGNED" not "APPROVED"
• Open proposals refresh silently without loading indicator
• After signing, "Done" button appears to dismiss the sheet

[dewabisma]

LGTM just small nit.