chore(nix): migrate lefthook from npm to nix

Move lefthook from pnpm devDependencies to nix flake buildInputs.
This ensures consistent versioning across the team via nix and
automatically installs git hooks when entering the devshell.

Changes:
- Add lefthook to flake.nix buildInputs
- Add `lefthook install` to shellHook for automatic setup
- Remove lefthook from package.json devDependencies
- Remove lefthook from pnpm-workspace.yaml catalog and onlyBuiltDependencies

Author: ryoppippi

flake.nix

@@ -37,6 +37,9 @@
 
               # security
               gitleaks
+
+              # git hooks
+              lefthook
             ];
 
             shellHook = ''
@@ -47,6 +50,9 @@
                 echo "📦 Installing dependencies..."
                 pnpm install --frozen-lockfile
               fi
+
+              # Install lefthook git hooks
+              lefthook install > /dev/null 2>&1
             '';
           };
         }

package.json

@@ -72,7 +72,6 @@
 		"ai": "catalog:dev",
 		"hono": "catalog:dev",
 		"knip": "catalog:dev",
-		"lefthook": "catalog:dev",
 		"msw": "catalog:dev",
 		"openai": "catalog:peer",
 		"publint": "catalog:dev",

pnpm-lock.yaml

@@ -16,7 +16,6 @@ catalogs:
     '@vitest/coverage-v8': ^4.0.15
     hono: ^4.9.10
     knip: ^5.72.0
-    lefthook: ^2.0.8
     msw: ^2.10.4
     publint: ^0.3.12
     tsdown: ^0.17.2
@@ -55,7 +54,6 @@ minimumReleaseAgeExclude:
 
 onlyBuiltDependencies:
   - esbuild
-  - lefthook
   - msw
 
 shellEmulator: true