feat(team): support queued team_send_message semantics

[piorpua]

Summary

• Add a queued team_send_message response contract so team tool calls can succeed immediately while the target slot is busy.
• Track active child turn runtime metadata, slow-turn state, runtime health, pending wakes, and suppressed wake release per team slot.
• Classify busy/disconnected ACP send failures so team scheduling can queue or recover without treating expected contention as an opaque error.

Test Plan

• just push -u origin feat/team-send-message-queued-semantics
  • migration immutability check passed
  • cargo fix --allow-dirty --allow-staged passed
  • cargo clippy --fix --workspace --allow-dirty --allow-staged -- -D warnings passed
  • cargo fmt --all passed
  • cargo nextest run --workspace: 6252 passed, 18 skipped
• Manual validation cases 1, 2, 3, 4, and 7 were checked against development logs and the local dev database.