Login / Import / Create / Settings were vertically centred in the content
column (align-self: center), which on tall screens left a dead band above
the page heading. Now top-aligned; horizontal centring unchanged.
New PasswordInput component wraps every password / PIN / passphrase field
with an eye button that toggles the text. Also: wallet-order drag&drop,
path-search sweep, settings panel sections, change-address policy.
