sandpiper-ai

Polish: add blank line separators between session blocks in read output

Docs sync: update concurrent-sessions.md to match implementation

Restore .sandpiper/standup.md to current main snapshot (NEW-B2)

Phase 3 integration: prompts/skills now use sandpiper-standup CLI

Phase 2 CLI: standup parser/liveness/read-write-cleanup with round-2 fixes