docs(DACMICU): specification and eval scripts

- Add specs/DACMICU.md: full design document covering the four pillars
  (Manus CLI, deterministic split, Ralph Loop, Fabric composition),
  architecture, competitive landscape, and adoption strategy
- Add test/eval/dacmicu-adoption.sh: measures LLM adoption rate across
  5 prompt patterns with scoring (0/1/2 per prompt)
- Add test/eval/dacmicu-fast.sh: lightweight 3-prompt eval for quick
  iteration testing

Author: micuintus