AfterDephantomize crosslinks a just-filled phantom and walks the whole orphan/delta graph reachable from it. It runs synchronously mid-round as a clone stores received files (sync.storeReceivedFile), before the round returns and long before the post-round CrosslinkContext sweep that already observes the deadline. That walk took no context and was bounded only by a 1,000,000- iteration safety cap, so on a large graph a clone could run for many multiples of its configured deadline with the process busy inside this exact call chain and no cancellation ever reaching it (#166).

Thread context.Context through AfterDephantomize, afterDephantomize, and crosslinkSingle, and poll ctx.Done() inside the work-stack loop every crosslinkCancelCheckStride pops -- the same stride-batched check linkBatch already uses in the whole-repository sweep. On cancellation the walk returns what it has crosslinked so far, matching how the batch sweep abandons its remaining candidates. The clone path (cloneSession.handleFile) and server push handler (handler.handleFile) pass their real request context through; the general sync loop, whose deadline is not threaded to handleFileCard, passes context.Background() to keep its behavior unchanged.

This is an additive, disjoint cancellation path: the post-round batch sweep and its existing cancellation tests are untouched.

Regression test TestAfterDephantomizeObservesCancellationMidWalk builds a root-plus-fanout delta graph larger than the stride and drives the walk with a context that goes live -> cancelled mid-walk, asserting the cascade stops early instead of crosslinking every node. check-in: a633f335c9 user: [email protected] tags: trunk