feat(FN-1185): inject agent rating feedback into runtime instructions

- Extend agent instruction resolution to append a Performance Feedback section with average score, trend, category breakdown, and recent comments when ratings exist
- Add rating-aware instruction resolution with graceful fallback when no store is configured, agent IDs are missing, or rating lookup fails
- Wire executor custom instruction loading to fetch agent rating summaries and include them in resolved instructions
- Expand agent-instructions tests to cover feedback formatting, trend indicators, comment limits, and fallback/error paths

packages/engine/src/executor.ts

@@ -581,7 +581,12 @@ export class TaskExecutor {
       const agents = await this.options.agentStore.listAgents({ role: role as AgentCapability });
       for (const agent of agents) {
         if (agent.instructionsText || agent.instructionsPath) {
-          return await resolveAgentInstructions(agent, this.rootDir);
+          try {
+            const ratingSummary = await this.options.agentStore.getRatingSummary(agent.id);
+            return await resolveAgentInstructions(agent, this.rootDir, ratingSummary);
+          } catch {
+            return await resolveAgentInstructions(agent, this.rootDir);
+          }
         }
       }
     } catch {