Containerize scraper and externalize credentials

Move DB host/user/password, Discord webhook, and log path to env vars
so the script can be deployed via Docker compose. Discord notifications
are now skipped silently when DISCORD_WEBHOOK is unset (the old
hardcoded webhook is removed pending rotation). Adds Dockerfile,
docker-compose.yml, requirements.txt, .env.example, and .gitignore for
the cyrion deployment.

.env.example

@@ -0,0 +1,16 @@
+# Knoebels scraper environment configuration.
+# Copy to .env on the deploy host and fill in real values.
+# Never commit the real .env.
+
+# PostgreSQL connection (phlegethon by default)
+DB_HOST=192.168.88.9
+DB_PORT=5432
+DB_USER=kuhnobowls
+DB_PASSWORD=
+
+# Optional Discord webhook for notifications.
+# Leave empty/unset to skip Discord calls entirely.
+DISCORD_WEBHOOK=
+
+# Log path inside the container. Mapped to the knb_logs named volume by compose.
+LOG_PATH=/var/log/kuh-no-bowls/kuh-no-bowls.log