chore: untrack .env files, rely on gitignore

caddy/.env and immich/.env were tracked despite .gitignore already
excluding .env — gitignore only applies to untracked paths, so these
kept diffing secrets into commits. Files stay on disk, just no
longer in git.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01DPXhxhLUopnuDm3dWeHd5C

immich/.env

@@ -1,6 +0,0 @@
-UPLOAD_LOCATION=/mnt/storage/media/photos
-DB_USERNAME=postgres
-DB_PASSWORD=postgres
-DB_DATABASE_NAME=immich
-DB_DATA_LOCATION=/mnt/storage/apps/immich/db
-TZ=America/Los_Angeles