Remove .env.* files from tracking and update .gitignore

.env.prod

@@ -1,9 +0,0 @@
-### Compiled or real environment variables should be used in production.
-### Configure MAILER_DSN to use SendGrid API transport.
-### Prefer storing SENDGRID_API_KEY using Symfony Secrets or real env vars.
-
-###> symfony/mailer ###
-# Example using SendGrid API key (replace with real secret via vault/secrets):
-# SENDGRID_API_KEY=SG.xxxxx
-MAILER_DSN=sendgrid+api://%env(resolve:SENDGRID_API_KEY)%@default
-###< symfony/mailer ###