docs(session): add restart-safe recovery workflow

Context:

- codex cli 중단 후에도 작업 품질과 맥락을 안정적으로 복구하기 위해

Changes:

- docs/00~07, 90 문서 세트 추가/정리

- commit convention 문서 및 .gitmessage-session.txt 템플릿 추가

- scripts/session/recover-context.sh 추가

- package.json에 session:recover 스크립트 추가

Validation:

- npm run session:recover

Session-State: session recovery docs, template, and script are in place

Session-Next: apply this commit format to feature and refactor commits

Session-Risks: legacy commits before this change do not include session trailers

.gitmessage-session.txt

@@ -0,0 +1,14 @@
+<type>(<scope>): <summary>
+
+Context:
+- 
+
+Changes:
+- 
+
+Validation:
+- 
+
+Session-State: 
+Session-Next: 
+Session-Risks: