A shared QML select box for choosing a program account (a token holding) that
matches given criteria (accountType + a state field such as the token
definitionId), listing matches with balances and emitting selectionChanged.
Registered in the wallet module's public QML.
Cherry-picked from feat/shared-wallet-token-holding-selector, reduced to the
reusable component only; the AMM swap/liquidity wiring and FFI account source
are reimplemented on the current (post swap + createPool) code.