The registry grows the state-level read ladder the persisted cache builds
on: checkpoint(session) snapshots every unit's {stateVersion, observedSeq,
state} row from the watermark cache; restoreFloor(checkpoint) anchors the
tail read one event below the lowest usable watermark (so a shrunk log is
provable); restore(checkpoint, events, baseSeq) refolds each unit from its
usable row (or from init over a full read), rejects rows a tail read cannot
fix (version mismatch / overreach with baseSeq > 0 => re-read from 0), and
returns both the snapshot and the refreshed rows for durable write-back.
ProjectionCheckpointRow/ProjectionCheckpoint are the persisted-row types
minus the record keys.
Lint: eslint --fix over the merge-crossed projection/command files (arrow
parens, trailing commas, unnecessary assertions), Extract<> replaces the
keyof-map & string intersections no-redundant-type-constituents rejects,
the fold-adapter's merge loop drops its non-null assertions for a
bounds-carrying cursor, one JSDoc line wrapped under max-len (api-catalog
regenerated). Snapshots: the four TUI goldens re-recorded for the merged
event-count shift (the durable command lifecycle adds one event to the
seeded diagnostics log). The headless advanced-toolchain snapshot passes
on CI and fails locally in this sandbox both with and without these
changes (30s child timeout — environment-bound, tracked in the ledger).
New zh pairs for the session-projection group and package READMEs (both
gained their missing language-switcher lines); the packages/README rows,
apiproxy README, and tool-todo README zh sides catch up with their edited
English; the group README's stale ProjectionProvider name becomes
ProjectionDefinition. RFC precision from review: asOfSeq is the last
event's seq (session.seq - 1, -1 empty; subscribed.lastSeq vocabulary) and
a new risk names the accepted dev-only staleness window when registry
churn changes the key set mid-session. Pairing re-recorded; 540 pairs
consistent.
