Send tab: recipient (cashaddr or legacy, testnet rejected), amount with
BCH/sat toggle and Max, 1-5 sat/B fee slider, live fee/total preview via
planSend. Sending goes plan -> approval-modal (To/Amount/Fee/Total) ->
ECDSA DER + SIGHASH_ALL|FORKID -> blockchain.transaction.broadcast, then
shows the txid with an explorer link. Confirmed coins are spent before
unconfirmed; dust change folds into the fee. Verified end to end against a
fake Fulcrum: broadcast tx re-parsed, sighash recomputed, signature checks.
Manifest declaring sidebar-panel, vault-derive, page-inject (https://*.x)
and approval-modal; registers the Wallet sidebar panel. Shows up in
Settings > Extensions and opens from the sidebar.