Extract T3 orchestration resume sequences without interpreting event bodies.

sequence/1 reads an event's sequence, a thread snapshot's snapshotSequence, or a shell snapshot's nested snapshotSequence. Arrays return their highest eligible sequence. Unknown event bodies still advance a cursor. Missing/invalid sequence fields and completion markers return nil.

Project-enrichment shell snapshots marked resolvedRepositoryIdentityRoots are always ignored: their high-water may precede replayed events on the wire. Advancing from that marker can skip replay if a consumer crashes partway.

advance/2 is monotonic. Commit the result only after consuming the entire chunk (and, for durable consumers, storing the corresponding application changes). A cursor alone does not make T3 replay durable: the server can fall back to a current-state snapshot when history is pruned or over its replay budget. Scope stored cursors to the environment and subscription/filter set.