* feat(sync): delta sync — large files move as content-defined chunks
Files over 4 MiB push as chunks/<sha256> pieces plus a manifests/<sha256>
chunk list keyed by the whole file's hash, so Op.Blob alone locates it and
the journal format is byte-identical. A 1-byte edit to a 20 MiB file now
transfers ~2 MB instead of ~21 MB, both directions; chunk boundaries come
from a rolling hash (restic/chunker), so front insertions stay cheap.
The hub reassembles whole blobs on demand (spool, verify, backfill, serve),
which is the entire backward-compatibility story: old clients ask for
blobs/<sha> and never learn anything changed. Proven by e2e tests that build
the real pre-change binary from the pinned merge-base commit.
The push skip-proof is one Exists per chunk — three cheaper proxies (local
basis, manifest existence, stored manifest content) each proved false or
forgeable across four CTO review rounds and are recorded in the code
comment. Hub-side, manifests are write-once and must name only chunks the
store holds; reassembly is bounded at 256 MiB against amplified manifests.
Also: per-file sync ceiling 32 -> 100 MiB; import refuses archives whose
journals reference content they do not hold (--allow-incomplete overrides).
Deploy hubs before clients: old hubs refuse chunk keys (push degrades to
offline-retry), and old clients cap reads at 32 MiB so 32-100 MiB files
report "blob corrupt on remote" until the client upgrades.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01R6nqxi5a9qcENmJvrgBJF7
* fix(test): fetch the pinned pre-delta commit on shallow CI clones
buildOldBinary archives the pinned merge-base sha, which a fetch-depth-1
actions/checkout does not have — all three old-binary e2e tests failed in
CI with exit 128 while passing on any full local clone. On archive failure,
fetch just that commit (--depth=1, one object; actions/checkout persists
credentials so the in-job fetch works) and retry. Verified against a real
GitHub shallow clone: archive fails, the single-sha fetch succeeds, archive
then yields the pre-delta tree.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01R6nqxi5a9qcENmJvrgBJF7
---------
Co-authored-by: Claude Fable 5 <noreply@anthropic.com>
The anti-lock-in story for cloud-hesitant users: export a project's
complete store (every device's journal + every blob, i.e. full history
and authorship) into a portable tar.gz, and import it as a fresh project
on any other hub — cloud → self-hosted or back.
The archive is simply the remote store layout plus a manifest, streamed
through the existing remote.Backend, so no server-side support is needed
and it works against every existing hub. Import verifies each blob's
content hash, rejects foreign tar entries, requires an empty target
project, and refuses journal-less archives. Reconnecting devices resume
exactly where they were, because their journals are byte-identical.
Docs: README + SKILL.md command tables, docs-site CLI reference section,
and a new step-by-step reference page (Migrate between hubs).
Co-authored-by: Claude Fable 5 <noreply@anthropic.com>
