fix(mobile): fold subagent lifecycle rows into one batch per spawn

[juliusmarminge]

Stacked on #10210.

Problem

Each subagent's progress and completion rendered as its own timeline row on mobile (three agents → three "Running …" rows plus their completions), while web folds a turn's spawns into one "Kicked off N subagents" row via collapseDerivedWorkLogEntries in session-logic.ts.

Fix

Mirror web's batching in the mobile work log:

• Same spawn-group keys (wf:<coordinator> for workflows, direct:<turn> for direct spawns), decided at the first row seen per taskId so later rows under synthetic turns cannot splinter the batch.
• Agent lifecycle rows pass the agent-internal filter even when bypassed or owned by another agent, as on web; that is how Codex children (all bypassed) and Claude workflow members reach the batch row.
• The batch row keeps the anchor's identity so it renders where the run launched.
• Background tasks (agentKind !== "agent") keep one row per task, as before.
• Web reads live agent state from its Agents panel; mobile has no such surface, so the row carries each member's latest lifecycle state, derives its own lifecycle from them (live while any member is, then the worst terminal state), and lists the members when opened. A Codex child's idle turn end counts as finished, and a finished coordinator settles members that never reported their own end. That lifecycle feeds the group summary and shimmer from fix(mobile): restore live tool shimmer and add a Thinking row #10173 unchanged.

Verification

• vp test run apps/mobile/src/lib/threadActivity.test.ts — 98 passed, including new tests that fold two direct spawns into one row and track it through running → one done → one failed, fold bypassed workflow members into the coordinator's batch and settle them with it, and finish a Codex child on idle; plus updated expectations for the resumed-agent and Antigravity batch cases.
• tsc --noEmit for apps/mobile, targeted lint and format.
• Simulator, same seeded turn (three agents: two running, one finished) on main and this branch.

Implemented by Claude Fable 5 in the Claude Code harness.

Note

Fold subagent lifecycle rows into one batch row per spawn in mobile threadActivity

• Replaces one-row-per-agent-task rendering with one aggregated row per workflow or direct-spawn batch in the mobile work log; shell, monitor, and plan tasks remain ordinary per-task rows.
• Agent task rows that were previously filtered as internal now reach feed derivation so they can be grouped by workflow, turn, or task ID into spawn batches.
• Adds helpers for batch lifecycle precedence (in-progress > failed > stopped > completed), member merging by task ID, label generation with live/failed/stopped member counts, and expanded-body formatting listing each member's title, status, and detail.
• Workflow coordinators are excluded from displayed member counts and details; a terminal coordinator settles unfinished workflow members to its own terminal state.
• Updates tests in threadActivity.test.ts to assert batch-row grouping, anchor identity, member counts, terminal states, and idle-as-completed behavior.
• Behavioral Change: isAgentInternalActivity now retains agent task rows with task IDs (including bypassed rows) for batch folding instead of filtering them; consumers of collapseDerivedWorkLogEntries will see fewer rows and new structured spawn metadata on WorkLogEntry.

^{Macroscope summarized a83379d.}

[github-actions]

Thread transfer impact

✅ Thread transfer remains within every enforced ceiling.

ℹ️ No successful main baseline artifact is available yet. This run establishes the initial measurement.

Provider	Metric	Main baseline	This PR	Impact	PR ceiling
Codex	Total thread wire	—	13.6 KiB	—	15.1 KiB	✅
Codex	Thread snapshot wire	—	7.0 KiB	—	7.3 KiB	✅
Codex	Live turn WebSocket wire	—	6.6 KiB	—	7.8 KiB	✅
Codex	Live turn WebSocket decoded	—	57.1 KiB	—	66.4 KiB	✅
Codex	Live turn messages	—	10	—	21	✅
Claude	Total thread wire	—	13.5 KiB	—	15.1 KiB	✅
Claude	Thread snapshot wire	—	7.0 KiB	—	7.3 KiB	✅
Claude	Live turn WebSocket wire	—	6.5 KiB	—	7.8 KiB	✅
Claude	Live turn WebSocket decoded	—	57.8 KiB	—	66.4 KiB	✅
Claude	Live turn messages	—	9	—	21	✅

Baseline: unavailable · PR result: a83379d · Source CI: success

Scenario and decoded snapshot size

10 historical turns, 5 command tools per turn, 878.9 KiB retained MCP result per historical turn, and a 1.05 MiB retained result in the measured turn.

• Codex decoded thread snapshot: 113.8 KiB
• Claude decoded thread snapshot: 114.5 KiB

Updated in place by a trusted workflow. PR artifacts are strictly validated and never executed.

[macroscopeapp]

Approvability

Verdict: Not approved

Macroscope's review found this PR not approvable — This PR changes the existing mobile work-log behavior by replacing individual agent lifecycle rows with stateful batches across direct spawns and workflows. The implementation spans filtering, aggregation, lifecycle derivation, and expanded rendering, making the change broader than a straightforward isolated fix.

^{You can add or adjust custom eligibility rules. Learn more.}