refactor(session-projection): compact checkpoint row fields to ver/seq/val
The persisted row (sessionId, key, stateVersion, observedSeq, state) becomes (sessionId, key, ver, seq, val) — the cache medium repeats these three names for every unit of every session, so the long forms dominated the JSON payload. ProjectionCheckpointRow and the checkpointRow zod spec rename together; the domain spec bumps to v3 (cache semantics: the old medium is discarded, not migrated). The unit-facing declaration keeps stateVersion — only the persisted/checkpoint row shape changes.
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@@ -574,19 +574,19 @@ export const SERVICE_API: readonly ServiceApiEntry[] = [
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},
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{
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signature: 'checkpoint(session: Session): ProjectionCheckpoint',
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jsDoc: '/**\n * State-level checkpoint of every registered unit for one session, read\n * from the watermark cache (missing cells fold lazily over the in-memory\n * log). This is the write side of the persisted projection cache: the\n * returned rows are the `(key → {stateVersion, observedSeq, state})` part\n * of the durable `(sessionId, key, stateVersion, observedSeq, state)`\n * rows. Every `state` is a DETACHED structured clone — never the live\n * cell reference: the watermark cache is this registry\'s authoritative\n * mutable state, and a caller reaching the live reference could corrupt\n * every subsequent snapshot and frame through it (plain JSON by the unit\n * contract, so the clone is total).\n * @param session - the session whose unit states are checkpointed.\n * @returns one row per registered key; empty when no unit is registered.\n */',
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jsDoc: '/**\n * State-level checkpoint of every registered unit for one session, read\n * from the watermark cache (missing cells fold lazily over the in-memory\n * log). This is the write side of the persisted projection cache: the\n * returned rows are the `(key → {ver, seq, val})` part of the durable\n * `(sessionId, key, ver, seq, val)`\n * rows. Every `val` is a DETACHED structured clone — never the live\n * cell reference: the watermark cache is this registry\'s authoritative\n * mutable state, and a caller reaching the live reference could corrupt\n * every subsequent snapshot and frame through it (plain JSON by the unit\n * contract, so the clone is total).\n * @param session - the session whose unit states are checkpointed.\n * @returns one row per registered key; empty when no unit is registered.\n */',
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},
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{
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signature: 'restoreFloor(checkpoint: ProjectionCheckpoint): number | undefined',
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jsDoc: '/**\n * The stored seq a {@link restore} tail read over `checkpoint` must start\n * at: one event BELOW the lowest usable watermark (a row is usable when\n * its `stateVersion` matches the live unit; an absent or mismatched row\n * pulls the floor to `0` — that key must refold the full log). The\n * one-below anchor is load-bearing: the tail then proves how far the\n * stored log still extends, so {@link restore} can detect a log that\n * shrank below a row\'s watermark (crash-repair truncation) instead of\n * serving the stale row as current — an empty tail read from the anchor\n * yields an end below every watermark and the restore rejects for a full\n * re-read.\n * @param checkpoint - persisted rows for one session (possibly stale or empty).\n * @returns the seq to hand the persistence `readFrom`, or `undefined`\n * when no unit is registered (no read needed — {@link restore} would\n * serve empty values regardless).\n */',
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jsDoc: '/**\n * The stored seq a {@link restore} tail read over `checkpoint` must start\n * at: one event BELOW the lowest usable watermark (a row is usable when\n * its `ver` matches the live unit\'s `stateVersion`; an absent or mismatched row\n * pulls the floor to `0` — that key must refold the full log). The\n * one-below anchor is load-bearing: the tail then proves how far the\n * stored log still extends, so {@link restore} can detect a log that\n * shrank below a row\'s watermark (crash-repair truncation) instead of\n * serving the stale row as current — an empty tail read from the anchor\n * yields an end below every watermark and the restore rejects for a full\n * re-read.\n * @param checkpoint - persisted rows for one session (possibly stale or empty).\n * @returns the seq to hand the persistence `readFrom`, or `undefined`\n * when no unit is registered (no read needed — {@link restore} would\n * serve empty values regardless).\n */',
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},
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{
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signature: 'viewCheckpoint(checkpoint: ProjectionCheckpoint): Partial<SessionProjectionMap>',
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jsDoc: '/**\n * View a checkpoint\'s rows without any log read: for every registered\n * unit whose row\'s `stateVersion` matches, serve the schema-validated\n * `view` of the stored state; mismatched or absent rows leave their key\n * absent (a cold or listing consumer treats it as not-yet-available and a\n * fuller read path refolds it). The zero-I/O rung of the read ladder —\n * values are as stale as their rows, never wrong.\n * @param checkpoint - persisted rows for one session (possibly stale or empty).\n * @returns whole values per key with a usable row; empty when none.\n */',
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jsDoc: '/**\n * View a checkpoint\'s rows without any log read: for every registered\n * unit whose row\'s `ver` matches, serve the schema-validated\n * `view` of the stored state; mismatched or absent rows leave their key\n * absent (a cold or listing consumer treats it as not-yet-available and a\n * fuller read path refolds it). The zero-I/O rung of the read ladder —\n * values are as stale as their rows, never wrong.\n * @param checkpoint - persisted rows for one session (possibly stale or empty).\n * @returns whole values per key with a usable row; empty when none.\n */',
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},
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{
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signature: 'restore(checkpoint: ProjectionCheckpoint, events: readonly SessionEvent[], baseSeq: number): { snapshot: ProjectionSnapshot; checkpoint: ProjectionCheckpoint }',
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jsDoc: '/**\n * Cold read: fold every registered unit over a stored log suffix, seeding\n * each from its checkpoint row when usable — the one read recipe (cached\n * state + forward tail replay + `view`) applied without a live `Session`.\n * Call with the events returned by a persistence\n * `readFrom(id, restoreFloor(checkpoint))` and that same floor as\n * `baseSeq`; the floor\'s one-below anchor makes the supplied end honest,\n * so a shrunk log is detected here. A row is usable iff its\n * `stateVersion` matches the live unit, it does not predate `baseSeq`\n * (`observedSeq >= baseSeq - 1`), and it does not claim events past the\n * supplied end (`observedSeq <= endSeq`); an unusable row is discarded\n * and its key refolds from `init` — which is only sound over the full\n * log, so a discarded row with `baseSeq > 0` throws (the caller re-reads\n * from seq 0, e.g. after a crash-repair truncation shrank the log below\n * a row\'s watermark).\n * @param checkpoint - persisted rows for one session (possibly stale or empty).\n * @param events - the stored events with `seq >= baseSeq`, in seq order.\n * @param baseSeq - the seq `events` starts at (its first event\'s seq when non-empty).\n * @returns the snapshot cut at the supplied log end (`asOfSeq` is the last\n * supplied event\'s seq, `baseSeq - 1` for an empty tail) plus the\n * refreshed checkpoint rows at that cut, ready for a durable write-back.\n */',
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jsDoc: '/**\n * Cold read: fold every registered unit over a stored log suffix, seeding\n * each from its checkpoint row when usable — the one read recipe (cached\n * state + forward tail replay + `view`) applied without a live `Session`.\n * Call with the events returned by a persistence\n * `readFrom(id, restoreFloor(checkpoint))` and that same floor as\n * `baseSeq`; the floor\'s one-below anchor makes the supplied end honest,\n * so a shrunk log is detected here. A row is usable iff its\n * `ver` matches the live unit\'s `stateVersion`, it does not predate `baseSeq`\n * (`seq >= baseSeq - 1`), and it does not claim events past the\n * supplied end (`seq <= endSeq`); an unusable row is discarded\n * and its key refolds from `init` — which is only sound over the full\n * log, so a discarded row with `baseSeq > 0` throws (the caller re-reads\n * from seq 0, e.g. after a crash-repair truncation shrank the log below\n * a row\'s watermark).\n * @param checkpoint - persisted rows for one session (possibly stale or empty).\n * @param events - the stored events with `seq >= baseSeq`, in seq order.\n * @param baseSeq - the seq `events` starts at (its first event\'s seq when non-empty).\n * @returns the snapshot cut at the supplied log end (`asOfSeq` is the last\n * supplied event\'s seq, `baseSeq - 1` for an empty tail) plus the\n * refreshed checkpoint rows at that cut, ready for a durable write-back.\n */',
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},
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],
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},
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@@ -1899,7 +1899,7 @@ export const TYPE_API: readonly TypeApiEntry[] = [
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},
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{
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name: 'ProjectionCheckpointRow',
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declaration: 'export interface ProjectionCheckpointRow {\n stateVersion: number;\n observedSeq: number;\n state: unknown;\n}',
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declaration: 'export interface ProjectionCheckpointRow {\n ver: number;\n seq: number;\n val: unknown;\n}',
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},
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{
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name: 'ProjectionDefinition',
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