fix(desktop): agent graph appears frozen while 0/7 operators are running (no heartbeat) #3878

What happened

When an Agent Graph fans out, the Desktop panel looks frozen even though work is in progress, which makes users think Maka is idle.

Observed in ScreenShot_2026-08-26_150336_899.png (7× local-read graph):

• Header shows Agent Graph Running · 0/7 settled for an extended period. settled only counts completed/failed/aborted/cancelled (agent-graph-panel.tsx: progress.settled), so 7 operators in running keep the counter at 0/7 with no intermediate movement.
• Each operator row shows a static blue dot (● Running / 运行中) + Open child task. The dot only changes color via CSS (apps/desktop/src/renderer/styles/*.css: .maka-agent-graph-status-dot → running/runnable → --status-running, completed → --success) with no pulse/animation, so 7 parallel local-read operators look like a static list.
• Chat shows Yield agent graph 64 ms and 调度完成，graph已创建 7个 local-read ... 正等待派发, then goes silent. The main transcript stops streaming while all work moves to child sessions, reinforcing the "stalled" impression.
• The panel's only Spinner is shown when loading && !snapshot (agent-graph-panel.tsx:452). Once a snapshot exists with status: active/waiting/closing, there is no global heartbeat (no spinner, progress bar, or elapsed timer).

User impact:

• With homogeneous fan-out (e.g. 7 local-read source-archaeology operators), the only visible change is 0/7 → 7/7 at the very end. Users in the 10-30s window often conclude the graph is stuck and press Stop Graph or reload.
• This is a liveness signal gap, not a performance bug: mod+n / scheduling is correct, but the UI provides no continuous "alive" feedback.

Expected:

• Running operators should animate (pulse) and the header should show a persistent heartbeat when status ∈ {active, waiting, closing}.
• Time dimension next to 0/7 (e.g. · Running 00:23 or Dispatched 3/7 · Settled 0/7) to break the static-number illusion.
• Optional per-operator live preview / incremental log line from childSessionId / snapshot.work[].instructionPreview so homogeneous local-read batches look differentiated.
• Indeterminate linear progress in the header while active is true, as a fallback heartbeat.

How to reproduce

1. Start a session that triggers an Agent Graph with fan-out (e.g. prompt that creates 7 local-read operators: pi, hermes-agent, oh-my-pi (can1357/oh-my-pi), openclaw, cline, kilocode, freebuff as in the screenshot).
2. Observe the Agent Graph panel header: Running · 0/7 settled (zh: 运行中 · 0/7 已结束).
3. Observe the 7 operator rows: all show static blue dot Running and no animation for >15s.
4. Observe the main chat: after 调度完成...已交棒给 graph no further streaming in the parent session.
5. Note the lack of any pulsing dot, spinner, elapsed time, or progress bar despite window.maka.graphs.subscribe receiving snapshots.

Screenshot: /home/me2seeks/ScreenShot_2026-08-26_150336_899.png (0/7, 7× SOURCE ARCHAEOLOGY OPERATOR — project: oh-my-pi / freebuff / cline / openclaw ..., all 运行中).

Environment

• Maka version or commit: 2b4c0deaa (main, 2026-08-26)
• OS and version: Linux (also visible on macOS/Windows — UI issue, not platform-specific)
• Surface: Desktop (Electron + Renderer, apps/desktop/src/renderer/agent-graph-panel.tsx)
• Node.js version: N/A (desktop build)

Logs, screenshots, or additional context

No runtime error. Graph scheduling is correct; only the presentation layer lacks liveness.

Relevant code:

• apps/desktop/src/renderer/agent-graph-panel.tsx:82-135 — copy (progress: settled/total, status: active/running...)
• apps/desktop/src/renderer/agent-graph-panel.tsx:390-410 — header progress copy.status(snapshot.status) · copy.progress(settled,total,omitted) + conditional stopAvailable/dismissAvailable
• apps/desktop/src/renderer/agent-graph-panel.tsx:452 — Spinner only on loading && !snapshot
• apps/desktop/src/renderer/agent-graph-panel.tsx:488-494 — operator row <span className="maka-agent-graph-status-dot"> + operatorStatus + wait
• apps/desktop/src/renderer/styles/*.css — .maka-agent-graph-status-dot { width:7px; height:7px; background: var(--muted-foreground) } with color overrides only, no animation
• apps/desktop/src/renderer/agent-graph-panel-visibility.ts — panel show/hide gating (not related to liveness)

Suggested minimal fix (incremental):

1. Add CSS pulse to running/runnable dots (1.5s scale+opacity loop) and a header heartbeat Spinner/pulse when snapshot.status === 'active'|'waiting'|'closing'.
2. Add elapsed ticker next to settled/total (derived from snapshot subscription age or scheduleRevision timestamp) or split into Dispatched/Running/Settled.
3. Surface per-operator incremental preview from snapshot.work / child session streaming to break homogeneous-list illusion.
4. Optional indeterminate header progress bar while active.

Related: the previous display-fix #3876 (⌘ N on Windows) was the same class of bug — correct behavior, wrong display signal.