Fix retained lane lifecycle attention projection

[yvette-carlisle]

Summary

• require terminal completion signal before phase-goal closeout
• preserve retained review/merge lifecycle blockers instead of stale writeback or contradictory closeout
• project terminal retained needs-attention ledger outcomes into attention_count and retained_attention worktree ownership

Validation

• cargo make checks
• cargo test -p decodex operator_status --all-features -- --test-threads=1
• cargo test -p decodex local_status_summary_counts_terminal_history_needs_attention_without_queue_candidate --all-features -- --test-threads=1
• cargo vstyle curate --language rust --workspace --all-features
• git diff --check
• semantic drift audit pass