* feat(subagent): align continuable human inbox controls
* fix: repair rebase documentation and close test persistence
* docs: refresh rebased module dependency graph
Session.loadThrough(seq) loops the existing prepend pager (200-message
pages) until the window covers the target seq, with a shared low-water
retarget for repeated calls, a no-progress guard against empty pages
still claiming history, and loadOlder's fail-soft error posture. Busy
state rides the existing loadingOlder snapshot bit.
Single RemoteError with a merge-extensible, domain-prefixed code map;
owners throw at the failure point; streams surface marked failures;
clients consume ctx.remote directly with isRemoteFailure as the only
discrimination point and construct no failure instances.
A steer or follow-up accepted while a turn is closing is now claimed by a
fresh turn at the driver's clean exit instead of stranding in the inbox;
cancellation and pre-step rejection still park accepted work. Continuable
subagent follow-ups accept image parts: the wire is upload-shaped, the Host
admits and persists each batch before inbox acceptance, and delivery is
refused when the child model declines image input. The queue dock renders
durable image thumbnails instead of an [image] text marker.
Fixes#3186
Dudu-0223