* fix(web): make mid-turn delta offsets step-relative
Reset in-flight text and client stream alignment at step boundaries so
resync seeds only the current step instead of duplicating prior steps.
* fix(web): dedupe resync-seeded messages by normalized content
The exact-JSON content signature missed duplicates when the two copies
differed by thinking signature, tool progress, part boundaries, or the
tool set (finished parallel tools leave running_tools). Reduce content
to concatenated stream text plus sorted tool-call ids and treat a
covered subset as the duplicate, merging the seed's tool progress into
the existing cards before dropping it.
e223549a79