* fix(sync): repair leaves and tags for check-ins the cascade links (#414)

A pulled check-in arrives as an announced phantom filled the next round, so the phantom-fill cascade links it. The session's closing sweep then found nothing left to link and skipped the leaf and tag-propagation repair, which gated on the sweep's own count: the check-in had an event row and no leaf row, and its parent stayed a leaf. The server handler had the same gap for a pushed artifact that fills a phantom.

AfterDephantomize and AfterDephantomizeBatch now return how many artifacts they linked. The sync client and the handler add that up over the session and close it with the new CrosslinkAfterCascades, which runs the repair once when the sweep or the cascades linked anything (repo-state-01 Section 7.3, RS-7.3-4), not once per file. The receive linker's cancellation paths gate on the same flag.

The repo-state harness gains a pull load: the first artifacts of a script are held and crosslinked locally, the rest pulled in process from a go-libfossil server holding them all. New cases repostate.7.3.pulled-child and repostate.7.6.pulled-retag, checked against fossil per artifact, each run as a .pull case too.

Tracked in #414.

* fix(sync): repair leaves of cascade links when a session fails (#414) check-in: 0035af8ac5 user: [email protected] tags: main, trunk

libfossil is a pure-Go implementation of the Fossil SCM, reading and writing the same .fossil SQLite repository format as upstream Fossil.

This is the first public release of code that previously lived in a private repository. The module path is github.com/danmestas/libfossil and the binary is named libfossil to avoid $PATH collisions with upstream fossil.

Included: - Repo lifecycle (create, clone), checkout/checkin, timeline, merge, diff, annotate, shun, tag, branch, bisect, stash, undo/redo - Sync-over-HTTP protocol (client and handler) - Two SQLite drivers: modernc (pure Go, default) and ncruces (wasm-capable) - Observer interfaces (SyncObserver, CheckoutObserver) with an optional OpenTelemetry implementation in observer/otel (separate submodule) - Deterministic simulation testing harness with BUGGIFY fault injection - Kong-based embeddable CLI under cli/ and a standalone binary under cmd/libfossil/ check-in: f5744359d3 user: [email protected] tags: trunk