docs: update READMEs for current state

chore: update ark-escrow submodule

fix: quote swap target amount from source amount

feat: enable Rust tracing in sample

feat: quote releasable amount for Bob

chore: update ark-escrow submodule

feat: support multiple fee outputs in sample

refactor: require fee address in sample

chore: update force settlement just env

refactor: rename force settlement env var

chore: simplify sample spend store

chore: unbuffer sample arbiter logs

feat: resume release from cached spend state

chore(submodule): point ark-escrow to rework spend store branch

refactor: use ark-escrow git submodule instead of path dep