chore: stop tracking lefthook-local.yml (#1454)

lefthook-local.yml is Lefthook's per-developer override file and is meant to
stay local (the shared hooks live in lefthook.yml). It is currently committed,
so it applies to everyone who clones the repo: a commit-msg hook in it appends
a personal Co-authored-by trailer to every contributor's commit.

Remove it from version control and add it to .gitignore so local overrides stay
local. lefthook.yml (the shared config) is unchanged.

Co-authored-by: Carlos Alcaraz <193642530+calcarazgre646@users.noreply.github.com>

Author: calcarazgre646

.gitignore

@@ -10,6 +10,9 @@ dist/
 .env.local
 .env.*.local
 
+# Lefthook per-developer overrides (not shared; see lefthook.yml for shared hooks)
+lefthook-local.yml
+
 # OS
 .DS_Store
 Thumbs.db