[lifecycle-RSK] RSK-16: Flip stream and turn-field reads #1805

Tracking

• Epic: [lifecycle-RSK] Run-state kernel #1790
• Size: 1 SP
• Blocked by: [lifecycle-RSK] RSK-10: Route stream, ask, and turn-field writes through events #1804, [lifecycle-RSK] RSK-05: Add the divergence comparison and a metric #1795, [lifecycle-RSK] RSK-17: Reset didFinishAbortingStream for each request #1801
• Design doc: docs/architecture/task-lifecycle-target-architecture.md (not yet on main)
• Ticket plan: docs/architecture/task-lifecycle-run-state-kernel-tickets.md (not yet on main)

Context

With writes routed, race R-1 fixed, and the comparison clean, the stream and turn reads move to the kernel. isStreaming must stay true until streamEnded. An abandon must not clear it, so cancelTask still waits for the old stream loop (ClineProvider.ts:3589-3600).

Developer Notes

• Precondition: [lifecycle-RSK] RSK-17: Reset didFinishAbortingStream for each request #1801 merged. The comparison shows zero divergence for the stream region and the turn fields on nightly, with an empty ignore list for them.
• Add getters for isStreaming (stream.tag === "live") and didFinishAbortingStream (stream.tag === "live" and stream.cleanupFinished).
• Flip the reads of isStreaming (2), didFinishAbortingStream (1), isWaitingForFirstChunk (1), didRejectTool (6), didAlreadyUseTool (3), didToolFailInCurrentTurn (1), and didCompleteReadingStream (2).
• Delete the seven fields and remove their writes from the helpers.

Exit criteria: no direct reads remain. Tests and E2E pass.

Reversibility: revert this PR.