recover still-running background tasks on reattach

A task row is officer's own invention, synthesised from the harness's system.task_started, and
nothing corresponding to it is ever written to Claude's transcript. So rebuildTranscript can only
produce user/tool/assistant rows, and sync:live deliberately carries no messages — which left the
background-task tray empty after a mid-task refresh even though the work was still running.

Fold the durable log on attach into started-minus-notified and hand that back on sync:live. The
same read now supplies the cursor, so this costs one query rather than two. Finished tasks are
excluded: replaying those would resurrect rows already seen to resolve.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

src/workspaces/officerdev/src/apps/Chat/types.ts

@@ -71,6 +71,8 @@ export type ChatMessage =
       done?: boolean;
     };
 
+export type RunningTask = { taskId: string; description: string; taskType?: string };
+
 export type TaskInfo = {
   taskName: string;
   taskDirName: string;
@@ -105,7 +107,20 @@ export type ServerMessage =
    * transcript came over HTTP a moment ago and there is no shared id to reconcile the two records by, so
    * this hands over the rest of the turn and the half-written paragraph, and nothing that would double up.
    */
-  | { type: 'sync:live'; sessionId: string; isGenerating: boolean; streamingText: string; cursor: number }
+  | {
+      type: 'sync:live';
+      sessionId: string;
+      isGenerating: boolean;
+      streamingText: string;
+      cursor: number;
+      /**
+       * Background tasks started and not yet finished. The single exception to "carries no messages": a
+       * task row has no counterpart in Claude's transcript — officer synthesises it — so rebuilding from
+       * the file cannot bring one back, and the tray came up empty on a refresh while work was still
+       * running. Finished tasks are excluded server-side.
+       */
+      runningTasks: RunningTask[];
+    }
   | { type: 'error'; message: string; errorCode?: string }
   | { type: 'stopped' }
   /** The agent process went away mid-turn. Recoverable — see the `cutoff` message role. */

src/workspaces/officerdev/src/hooks/useChat.ts

@@ -355,6 +355,19 @@ export function useChat(initialSessionId?: string, initialModel?: string | null,
           streamingRef.current = msg.streamingText;
           flushStreaming();
         }
+        // The one thing the transcript genuinely cannot supply. Appended rather than spliced into place:
+        // a task row carries no timestamp to sort by, so a recovered one lands at the end of the
+        // conversation instead of where it was started. The tray reads by taskId and renders correctly
+        // either way, and the alternative is inventing an ordering the record does not contain.
+        if (msg.runningTasks?.length) {
+          setMessages((prev) => {
+            const known = new Set(prev.filter((m) => m.role === 'task').map((m) => m.taskId));
+            const recovered = msg.runningTasks
+              .filter((t) => !known.has(t.taskId))
+              .map((t): ChatMessage => ({ role: 'task', ...t }));
+            return recovered.length ? [...prev, ...recovered] : prev;
+          });
+        }
         break;
       }