A continuable background child (the default backgroundMode for both
delegation tools) never received the parent session's explicit
sandbox/approval overrides: materialization applied only child
composition, so a danger-full-access parent produced workspace-write
children whose every out-of-workspace operation raised an approval
prompt.
Move the one-shot driver's capture/append pair into the shared
child-agent module (captureDelegatedPolicyOverrides /
appendDelegatedPolicyOverrides) and call it from both paths:
startContinuable captures before its first await, only fresh
materialization appends the source-tagged events (after any fork seed),
and a cold resume replays the persisted delegation events instead of
re-capturing the parent.
Adds the continuable inheritance unit suite, the ACP snapshot scenario
subagent-continuable-inheritance (fails without the fix), the
continuable policy-inheritance Agent Note, and the seam-level README
contract, with bilingual counterparts.
Fixes#1692
64e0fbfd6d