Show Mission timeline compaction in compact watch

[uesugitorachiyo]

Summary

• exposes timeline_compaction_bound in Mission aggregate summaries
• includes the signal in compact watch and JSONL watch output
• updates Mission aggregate fixtures to include timeline compaction provenance

Verification

• go test ./internal/cli -run 'TestMissionAggregate' -count=1
• go test ./... -count=1
• go vet ./...
• go build -o /tmp/ao-command ./cmd/ao-command
• git diff --check

Note: this repo has no scripts/production-readiness.sh.