v0.32.0 — message gate - fold at the first assistant message after the close, drop the unreachable successor-anchor defer

• Behavior (product owner ruling, superseding v0.14's G2): the fold
  gate now opens at the FIRST assistant message that follows the close
  result — any content counts (report text, a tool-call-only step,
  reasoning-only). The old text-only requirement held folds open through
  the common handoff shape — end task A, immediately task_begin task B,
  deliver A's report later — where A's gate stayed shut waiting for text
  that only landed deep inside B's span (found live on the MasterGoUI
  session: the 插件侧源码审查 → up 仓库与测试脚本审查 handoff folded two
  steps late, only after B's own fold). The lifecycle discipline still
  directs the model to deliver the report in that message; the gate only
  verifies the message exists. Tool copy and the system-prompt section
  updated to the new mechanics ("make the next message the report — the
  fold fires as soon as it lands").
• Removed: the successor-anchor defer (gate ②) and the drain's
  successor-anchor computation, together with the successorAnchors
  parameter of deferredArchivePlan. History: under v0.14's design the
  region ran to the last surface node trimmed AT the first still-open/
  pending successor anchor, so the defer protected the deliverable from
  being stranded outside the span. v0.16.0 pinned the region to
  begin..close exactly (deliverable stays on the surface; a later task's
  region sweeps it), voiding that rationale — and since anchors are
  begin-message seqs, the first post-close assistant message can never
  sit after the earliest successor anchor, making the defer branch
  unreachable. This also subsumes the 0.31.2 ghost-row filter's only
  consumer; the settled-row skip when picking entries remains.
• Tests: gate cases rewritten for the message semantics (wait only
  when NO assistant message follows the close; tool-call-only and
  whitespace-only messages open it); drain tests reshaped — the headline
  case is exactly the handoff shape above (elder folds in the same pass
  as the successor, no defer), plus wait-skip and next-pass retry.
  120/120 offline tests pass.

npm: dsh-taskfold@0.32.0