refactor: move nixos-manual to reference/ + graphifyignore

.graphifyignore

@@ -2,3 +2,4 @@ graphify-out/
 .graphify-cache/
 .obsidian/
 .trash/
+reference/nixos-manual/

reference/nixos-manual/_index.md

@@ -13,7 +13,7 @@ NixOS 25.11 stable("Xantusia") 매뉴얼의 CommonMark 소스. nixpkgs `nixos-25
 - **온라인 렌더링**: https://nixos.org/manual/nixos/stable/
 - **상위**: https://github.com/NixOS/nixpkgs/tree/nixos-25.11/nixos/doc/manual
 - **가져온 날짜**: 2026-04-08
-- **로컬 위치**: `~/obsidian/dev/nixos-manual/`
+- **로컬 위치**: `~/obsidian/reference/nixos-manual/`
 
 ## 구조
 
@@ -47,8 +47,8 @@ cd /tmp && rm -rf nixpkgs-manual-fetch
 git clone --depth=1 --filter=blob:none --sparse \
   --branch nixos-26.05 https://github.com/NixOS/nixpkgs.git nixpkgs-manual-fetch
 cd nixpkgs-manual-fetch && git sparse-checkout set nixos/doc/manual
-rm -rf ~/obsidian/dev/nixos-manual/{administration,configuration,development,installation,release-notes,*.md,*.nix,*.json}
+rm -rf ~/obsidian/reference/nixos-manual/{administration,configuration,development,installation,release-notes,*.md,*.nix,*.json}
-cp -R /tmp/nixpkgs-manual-fetch/nixos/doc/manual/. ~/obsidian/dev/nixos-manual/
+cp -R /tmp/nixpkgs-manual-fetch/nixos/doc/manual/. ~/obsidian/reference/nixos-manual/
 # _index.md(이 파일)는 보존
 ```