Update flow diagrams for event bus architecture, cancel cleanup, and SubscribeEvents

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/claude-agent)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

docs/architecture/flows/monitor-album-stream-manual.puml

@@ -113,6 +113,21 @@ note right #lightblue: "Download started"
 Workflow ->> Client: MonitorAlbumResponse
 note right #lightgreen: Final result
 
+== Cancel Cleanup (Disconnect or Cancel Message) ==
+
+note over Client, QBit #salmon
+**Manual Mode: Disconnect = Cancel**
+
+When client disconnects or sends CancelRequest:
+1. Workflow context is cancelled (stops further processing)
+2. If torrent was added to qBit: **DeleteTorrent(hash)** removes it + files
+3. If download record exists: marked as **cancelled** in DB
+4. workflow_run marked as **cancelled** in DB
+5. All events persisted to album_events for audit trail
+
+Cleanup uses a fresh context (not the cancelled one).
+end note
+
 == Decision Points Summary ==
 
 note over Client, QBit #lightyellow