Add 3 new streaming apps with explicit output declarations:
- streaming-clock.ds: output hours, minutes, seconds (tick private)
- streaming-stats.ds: output total, average, max (sum private)
- streaming-mood.ds: output mood, energy, color (clicks private)
Add compose-dashboard.ds that receives all 4 streams via unique
relay channels (/stream/default, /stream/clock, /stream/stats,
/stream/mood) into a single dashboard view.
Each app demonstrates selective signal registration — only declared
outputs are streamed, internal state remains private.
