Move database configuration from build-time to runtime environment variables

Problem

Database configuration (database.properties, mongo.properties) is currently generated at Docker image build time via printf in the Dockerfile (line 28-29). This has several drawbacks:

1. Changing any setting requires rebuilding the image — admins can't tune pool sizes, timeouts, or credentials without a full rebuild
2. New pool settings aren't exposed — the HikariCP connection pool settings (pool.maximumPoolSize, pool.minimumIdle, pool.leakDetectionThreshold, etc.) added in #800 have no way to be configured in a standard deployment
3. Secrets baked into image layers — DB_PASS is written via printf in a RUN step, making it visible in docker image history

Proposed solution

Replace the build-time printf with a runtime entrypoint script that generates database.properties and mongo.properties from environment variables when the container starts.

Benefits

• Change settings by restarting the container, no rebuild needed
• Pool tuning via .env or docker-compose.yml (e.g. DB_POOL_MAX_SIZE=20)
• Secrets only exist at runtime, not in image layers
• Standard Docker pattern that admins expect

Example

# docker-compose.yml
environment:
  - DB_HOST=secshep_mariadb
  - DB_PORT=3306
  - DB_USER=root
  - DB_PASS=secret
  - DB_SCHEMA=core
  - DB_POOL_MAX_SIZE=10
  - DB_POOL_MIN_IDLE=2
  - DB_POOL_LEAK_DETECTION_THRESHOLD=60000
  - MONGO_HOST=secshep_mongo
  - MONGO_PORT=27017

An entrypoint script would generate the properties files from these env vars (with sensible defaults) before starting Tomcat.

Related

• #536 — connection exhaustion issue (motivation for pool settings)
• #800 — connection pooling implementation (adds configurable pool settings)

Start with the Dockerfile at lines 28-29 and inspect the existing database.properties and mongo.properties generation, then review the docker-compose.yml environment examples. Add a runtime entrypoint that creates both files before Tomcat starts, including the pool settings and sensible defaults. Done means configuration changes work after a restart and DB_PASS is not present in Docker image history.