feat: 분류 체계 전면 개편 — taxonomy + document_type + confidence

- config.yaml: 6개 domain × 3단계 taxonomy + 13개 document_types 정의
- classify.txt: 영문 프롬프트, taxonomy 경로 기반 분류 + 분류 규칙 주입
- classify_worker: taxonomy 검증, confidence 기반 분류, document_type 저장
- migration 008: document_type, importance, ai_confidence 컬럼
- API: DocumentResponse에 document_type, importance, ai_confidence 추가

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

config.yaml

@@ -40,6 +40,66 @@ nas:
   mount_path: "/documents"
   pkm_root: "/documents/PKM"
 
+# ─── 문서 분류 체계 ───
+taxonomy:
+  Philosophy:
+    Ethics: []
+    Metaphysics: []
+    Epistemology: []
+    Logic: []
+    Aesthetics: []
+    Eastern_Philosophy: []
+    Western_Philosophy: []
+  Language:
+    Korean: []
+    English: []
+    Japanese: []
+    Translation: []
+    Linguistics: []
+  Engineering:
+    Mechanical: [Piping, HVAC, Equipment]
+    Electrical: [Power, Instrumentation]
+    Chemical: [Process, Material]
+    Civil: []
+    Network: [Server, Security, Infrastructure]
+  Industrial_Safety:
+    Legislation: [Act, Decree, Foreign_Law, Korea_Law_Archive, Enforcement_Rule, Public_Notice, SAPA]
+    Theory: [Industrial_Safety_General, Safety_Health_Fundamentals]
+    Academic_Papers: [Safety_General, Risk_Assessment_Research]
+    Cases: [Domestic, International]
+    Practice: [Checklist, Contractor_Management, Safety_Education, Emergency_Plan, Patrol_Inspection, Permit_to_Work, PPE, Safety_Plan]
+    Risk_Assessment: [KRAS, JSA, Checklist_Method]
+    Safety_Manager: [Appointment, Duty_Record, Improvement, Inspection, Meeting]
+    Health_Manager: [Appointment, Duty_Record, Ergonomics, Health_Checkup, Mental_Health, MSDS, Work_Environment]
+  Programming:
+    Programming_Language: [Python, JavaScript, Go, Rust]
+    Framework: [FastAPI, SvelteKit, React]
+    DevOps: [Docker, CI_CD, Linux_Administration]
+    AI_ML: [Large_Language_Model, Computer_Vision, Data_Science]
+    Database: []
+    Software_Architecture: []
+  General:
+    Reading_Notes: []
+    Self_Development: []
+    Business: []
+    Science: []
+    History: []
+
+document_types:
+  - Reference
+  - Standard
+  - Manual
+  - Drawing
+  - Template
+  - Note
+  - Academic_Paper
+  - Law_Document
+  - Report
+  - Memo
+  - Checklist
+  - Meeting_Minutes
+  - Specification
+
 schedule:
   law_monitor: "07:00"
   mailplus_archive: ["07:00", "18:00"]