Fetch Historical Transcript Data

Nucleic-Session: 11465D90-A8F3-43AA-A1DC-37EA1EC1B909
Co-authored-by: Nucleic <[email protected]>

NucleicRemote/NucleicRemote/Models/HostConnection.swift

@@ -555,11 +555,25 @@ final class HostConnection {
         case .transferAccept, .transferReject, .transferReady, .transferCommitted, .transferChunkAck:
             // Session-transfer replies (mesh P5) only reach a *source* Mac; a phone is never one.
             break
-        case .transcriptChunk, .transcriptFetchComplete, .transcriptUnavailable:
-            // Full-transcript fetch replies (mesh sync) only arrive in response to a
-            // `fetchTranscript` this device sent. A phone pulls full history on demand via a
-            // dedicated fetch path (not this subscribe stream), so nothing to do here yet.
-            break
+        case .transcriptChunk(let chunk):
+            // One ordered slice of the full-history fetch we started on open. Match on request id so
+            // a stale batch from a previous open (session switched underneath us) is ignored.
+            guard chunk.requestID == transcriptFetchRequestID, chunk.sessionID == openSessionID else { break }
+            // De-dup against the tail/live stream and advance the warm-resubscribe cursor exactly like
+            // a snapshot/events batch, then hand the fresh (older) events to RemoteStore, which merges
+            // them into the transcript by seq rather than appending.
+            let fresh = chunk.events.filter { !seenSeq.contains($0.seq) }
+            seenSeq.formUnion(chunk.events.map(\.seq))
+            if let maxSeq = chunk.events.map(\.seq).max() { openMaxSeq = max(openMaxSeq ?? 0, maxSeq) }
+            if !fresh.isEmpty { callbacks.openBackfill(EventBatch(sessionID: chunk.sessionID, events: fresh)) }
+        case .transcriptFetchComplete(let done):
+            // Terminal success — every batch shipped. Clear the in-flight id; the cursor/dedup state
+            // is already advanced by the chunks above.
+            if done.requestID == transcriptFetchRequestID { transcriptFetchRequestID = nil }
+        case .transcriptUnavailable(let un):
+            // The host holds no transcript for this session (or can't serve the format). The cold tail
+            // still shows; there's just no deeper history to add. Clear the in-flight id.
+            if un.requestID == transcriptFetchRequestID { transcriptFetchRequestID = nil }
         case .toolSummaries:
             // Collapsed Bash summary lines the owner pushes to peer *Macs* (mesh session sync).
             // The phone renders its own deterministic command summaries, so it ignores these.