refactor: merge design-roles and find-skill into plan, fix Built-in Verification principle (#768) (#768)

Abolish design-roles and find-skill as separate pipeline stages. Plan now
handles both requirements analysis and architecture design directly.

Fix the Built-in Verification principle: verifiers must actually execute
artifacts to test whether they work, not just review code. The principle
is now enforced consistently across plan (design time), write-definition
(self-check), and verify-test (semantic review).

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

Author: FL4TLiN3

README.md

@@ -135,12 +135,6 @@ Runs (create-expert) Enter:Select b:Back q:Quit
  > ✓ create-expert Form a team named bash-gaming. They build indie CLI games…
    | \
    | ✓ @create-expert/plan Create a Perstack expert definition for team…
-   | ✓ @create-expert/design-roles Design the technical architecture…
-   | | \
-   | | ✗ @create-expert/find-skill
-   | | ✗ @create-expert/find-skill
-   | | ○ @create-expert/find-skill
-   | | /
    | ✓ @create-expert/build Build the bash-gaming perstack.toml expert…
    | | \
    | | ✓ @create-expert/test-expert Build a word puzzle game 'lexicon'…