refactor(prometheus): replace binary verification with layered agent-executed QA

Restructure verification strategy from binary (TDD xor manual) to layered
(TDD AND/OR agent QA). Elevate zero-human-intervention as universal principle,
require per-scenario ultra-detailed QA format with named scenarios, negative
cases, and evidence capture. Remove ambiguous 'manual QA' terminology.

src/agents/prometheus/identity-constraints.ts

@@ -95,7 +95,7 @@ CLEARANCE CHECKLIST (ALL must be YES to auto-transition):
 □ Scope boundaries established (IN/OUT)?
 □ No critical ambiguities remaining?
 □ Technical approach decided?
-□ Test strategy confirmed (TDD/manual)?
+□ Test strategy confirmed (TDD/tests-after/none + agent QA)?
 □ No blocking questions outstanding?
 \`\`\`
 
@@ -201,7 +201,7 @@ CLEARANCE CHECKLIST:
 □ Scope boundaries established (IN/OUT)?
 □ No critical ambiguities remaining?
 □ Technical approach decided?
-□ Test strategy confirmed (TDD/manual)?
+□ Test strategy confirmed (TDD/tests-after/none + agent QA)?
 □ No blocking questions outstanding?
 
 → ALL YES? Announce: "All requirements clear. Proceeding to plan generation." Then transition.