Document resumable transcription and replay

docs/internal/manifest.md

@@ -50,6 +50,43 @@ The model admits these stage states:
 - `stale`
 - `interrupted`
 
+### Transcribe-owned speaker state
+
+A `transcribe` stage record may carry `transcribe_state_version: 1` and a
+`transcribe_speakers` map keyed by the existing derived speaker ID. The version
+is the authority marker: a versioned empty map means that no earlier speaker
+completion is reusable. Absence of both fields is accepted as legacy
+aggregate-only state so current Narratio can read older manifests.
+
+Each map entry represents one completed speaker only. It binds a versioned
+fingerprint to the session-relative audio path, audio SHA-256 and size, one
+canonical `transcript_raw` output with its path, SHA-256 and size, and the
+producer run ID. Paths must be canonical and session-relative, checksums must
+be lowercase SHA-256 values, and the record and output producer identities
+must agree. Other stages cannot carry this transcribe-owned state.
+
+Transcribe reconciles this collection against the current prepared audio set
+and observable WhisperX semantics. Missing or corrupt regular outputs become
+work; unsafe or non-regular evidence is rejected. It saves the reconciled
+collection before HTTP dispatch and saves a detached candidate after each
+validated completion. Only after a save succeeds is the candidate installed as
+live authority. Canonical bytes produced before an unsuccessful save are not a
+completion record.
+
+Aggregate transcribe status still describes the whole invocation. A failed,
+running, stale, or interrupted aggregate may therefore retain reusable speaker
+records, while aggregate outputs are declared only after the current
+collection is complete. Ordinary retry reconciles and reuses those records.
+Force first checkpoints an empty current collection, preventing later retries
+from reviving pre-force results.
+
+Older aggregate-only transcribe success is conservatively regenerated once
+when transcribe is selected because it does not bind individual outputs to the
+audio bytes used. The session-manifest schema identifier remains
+`narratio.session-manifest.v1`; this additive state is accepted by current
+Narratio, but older strict-decoding binaries may reject manifests after these
+fields have been written.
+
 ### Analyze-owned artifact state
 
 Every `analyze` stage record carries `analyze_state_version: 1` and an
@@ -156,10 +193,10 @@ establish a current immutable snapshot.
 
 Manifest replacement provides atomic visibility, not a crash- or power-loss
 durability guarantee. Callers reload after a returned save error before retrying.
-An analyze checkpoint error leaves the prior manifest as per-artifact authority.
-The runner then attempts to persist the bounded failed/stale retry collection;
-if that terminal save also fails, its error is joined with the originating
-failure and the next invocation must reconcile from the last readable manifest.
+A transcribe or analyze checkpoint error leaves the prior manifest collection
+as authority. The runner then attempts to persist the aggregate failure; if
+that terminal save also fails, its error is joined with the originating failure
+and the next invocation must reconcile from the last readable manifest.
 
 ## Execution Semantics
 
@@ -193,11 +230,11 @@ only fields returned by the new result. Marking a record stale does not clear
 those details because resume validation and diagnosis may still require them
 before execution begins.
 
-Aggregate lifecycle clearing deliberately preserves the analyze-owned
-per-artifact collection. This lets later reconciliation replace only evaluated
-entries without erasing unrelated current results. Other stages retain their
-existing aggregate-only lifecycle behavior and are forbidden from carrying the
-analyze-specific fields.
+Aggregate lifecycle clearing deliberately preserves both the transcribe-owned
+speaker collection and the analyze-owned per-artifact collection. This lets
+later reconciliation replace only non-current entries without erasing durable
+completions. Other stages retain aggregate-only lifecycle behavior and are
+forbidden from carrying either collection.
 
 A stage may explicitly return a skipped disposition and stable reason. The
 runner persists that outcome in the session manifest, clears older outputs,
@@ -228,7 +265,7 @@ evidence and focused durable validators:
 | Work | Reuse authority | Focused owners |
 | --- | --- | --- |
 | prepare | aggregate semantic fingerprint | [prepare](stage-prepare.md) |
-| transcribe | aggregate semantic fingerprint | [transcribe](stage-transcribe.md), [WhisperX](../integrations/whisperx.md) |
+| transcribe speakers | aggregate semantic fingerprint plus per-speaker input/output reconciliation | [transcribe](stage-transcribe.md), [WhisperX](../integrations/whisperx.md) |
 | merge | aggregate semantic fingerprint | [merge](stage-merge.md), [Seriatim](../integrations/seriatim.md) |
 | polish | aggregate semantic fingerprint | [polish](stage-polish.md), [Audita](../integrations/audita.md) |
 | normalize | aggregate semantic fingerprint | [normalize](stage-normalize.md), [Seriatim](../integrations/seriatim.md) |
@@ -310,6 +347,7 @@ where the last session transition can require operator interpretation.
 - Remote commit model and readers: `internal/artifacts/remote_commit.go`,
   `internal/artifacts/current_state_commit.go`,
 - Persistence and validation: `internal/manifest/store.go`
+- Transcribe speaker state: `internal/manifest/transcribe_state.go`
 - Package tests: `internal/manifest/*_test.go`
 - Assembled execution behavior: `internal/app/runner_test.go`,
   `internal/app/run_stage_test.go`