fix: typo and navigation corrections from code review

- Fix "Anthropics" → "Anthropic" typo in query-engine.md Mermaid diagram
- Fix permission-system.md "이전" nav link to point to command-system.md

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

docs/ko/level-2-systems/permission-system.md

@@ -360,6 +360,6 @@ type PermissionDecisionReason =
 
 ## Navigation
 
-- 이전: [Tool 시스템](tool-system.md)
+- 이전: [커맨드 시스템](command-system.md)
 - 다음: [에이전트 오케스트레이션](agent-coordinator.md)
 - 상위: [목차](../README.md)

docs/ko/level-2-systems/query-engine.md

@@ -15,7 +15,7 @@ graph TD
     QE["QueryEngine\n(src/QueryEngine.ts)"]
     ASK["ask()\n편의 래퍼"]
     QUERY["query()\n(src/query.ts)"]
-    CLAUDE["services/api/claude.ts\nAnthropics API 클라이언트"]
+    CLAUDE["services/api/claude.ts\nAnthropic API 클라이언트"]
     TOOLS["Tool 시스템\n(src/Tool.ts)"]
     COST["cost-tracker.ts\n비용·토큰 집계"]
     COMPACT["services/compact/\n컨텍스트 압축"]