chore: ignore .env* files

Keep local environment files (.env.local, etc.) out of git so secrets and
machine-specific config are never accidentally committed.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Signed-off-by: Connor Tsui <connor.tsui20@gmail.com>

Author: connortsui20

.gitignore

@@ -3,3 +3,4 @@ dist
 .scratch/
 /target
 .vercel
+.env*