fix(mobile): a running subagent's card stays visible after its turn ends

[roprgm]

Problem

A subagent keeps running after the turn that started it ends, usually within seconds. When that turn settles, mobile folds its work into "Worked for X", including the subagent's card. The card disappears while the subagent is still working, and the collapsed row reads as finished work.

Change

deriveThreadFeedRunFolds already keeps notifications, handoffs, and prominent items outside the fold. A subagent card whose subagent is still active (isOrchestrationV2WorkActive) now stays outside too. Once the subagent settles, the card folds as before.

Web folds settled turns with the same rule (deriveTurnFolds in MessagesTimeline.logic.ts), so it likely needs the same change.

Verification

• vp test run apps/mobile/src/lib/threadActivity.test.ts: a running subagent's card stays visible after its run settles and folds once it completes. The new test fails without the change.
• Mobile typecheck and targeted lint pass.
• Manual: physical iPhone 17 Pro (iOS 26.7.1), Release build. A delegated subagent ran five minutes after its turn ended: the card stayed visible while it worked, then folded into "Worked for X" next to the finish notice once it completed.

Before: running card only inside the expanded fold	After: running card stays visible	After: folds once finished

Made with Claude Opus 5.5 in Claude Code, running in T3 Code.

[roprgm]

Superseded by upstream pingdotgg#16878, which keeps running subagent cards outside the fold on mobile and web.