remove pnpm install on post-checkout and post-merge in main lefthook.yml; fix typo in .gitignore

Author: KKonstantinov

.gitignore

@@ -53,4 +53,5 @@ dist/
 # Conformance test results
 results/
 
-.lefthook-local.yml
+# Ignore local lefthook configuration
+lefthook-local.yml

lefthook.yml

@@ -34,14 +34,4 @@ pre-push:
           run: pnpm run build:all
           fail_text: |
               💡 To catch build issues earlier, enable the pre-commit hook:
-              cp lefthook-local.example.yml lefthook-local.yml
-
-post-checkout:
-    jobs:
-        - name: 'Install Dependencies'
-          run: pnpm install
-
-post-merge:
-    jobs:
-        - name: 'Install Dependencies'
-          run: pnpm install
+              cp lefthook-local.example.yml lefthook-local.yml