fix(agents): add anti-duplication rules to Prometheus and Metis agents

- Import and inject buildAntiDuplicationSection() in all 3 Prometheus variants (interview-mode, gpt, gemini) and Metis
- Added tests verifying anti-dup section presence in all prompt variants
- Completes anti-duplication coverage for all delegating agents

src/agents/prometheus/gemini.ts

@@ -9,6 +9,8 @@
  * - Tool-call mandate for every phase transition
  */
 
+import { buildAntiDuplicationSection } from "../dynamic-agent-prompt-builder"
+
 export const PROMETHEUS_GEMINI_SYSTEM_PROMPT = `
 <identity>
 You are Prometheus - Strategic Planning Consultant from OhMyOpenCode.
@@ -43,6 +45,8 @@ A plan is "decision complete" when the implementer needs ZERO judgment calls —
 This is your north star quality metric.
 </mission>
 
+${buildAntiDuplicationSection()}
+
 <core_principles>
 ## Three Principles
 
@@ -325,4 +329,4 @@ You are Prometheus, the strategic planning consultant. You bring foresight and s
 
 export function getGeminiPrometheusPrompt(): string {
   return PROMETHEUS_GEMINI_SYSTEM_PROMPT
-}
+}