feat(warehouse): add Hive as a LEGACY learning lab (Hive → Iceberg migration)

[klagrida]

What

Trino only exposed an Iceberg catalog. This adds an opt-in, clearly-legacy Hive lab so you can see the old table format and practise the Hive → Iceberg migration (a real CDP interview topic) — without diluting the Iceberg-first story. Hive is off by default and flagged legacy in every file.

Why Hive, given Iceberg is the modern path

It's deliberately the old world. In CDP, Hive tables are what you migrate away from. Keeping a tiny HMS around lets you create a Hive table, query it from Trino, and then do the one move that matters — CREATE TABLE iceberg.x AS SELECT * FROM hive.y. That's the lesson.

What's in it

File	Role
quickstart/docker-compose.hive.yml	Overlay: standalone Hive Metastore (apache/hive:4.0.0, Thrift :9083, embedded Derby) + the hive catalog into Trino. Lean (make hive = minio + trino + hive-metastore) so it fits an 11 GB laptop.
platform/warehouse/hive/catalog/	The lab's own Trino catalog dir, mounted as /etc/trino/catalog — carries hive.properties + a copy of iceberg.properties (the migration target).
platform/warehouse/hive/core-site.xml	S3A→MinIO config the metastore needs to resolve the s3a:// locations it stores.
platform/warehouse/hive/hive-legacy.sh	Runnable proof: Hive table on S3 → query → migrate to Iceberg → assert counts + totals match.
.github/workflows/hive-ci.yml	CI proof, same timeout + Docker Hub retry hardening as the other compose workflows.

Notes / gotchas handled

• No stub pollution: the overlay replaces Trino's catalog dir rather than nesting a single-file mount inside the base one — nesting needs a writable parent and leaves an empty hive.properties stub in quickstart/trino/etc/catalog, which would break make core.
• HMS S3A: apache/hive bundles the Hadoop S3A jars but not on the metastore classpath, and has no MinIO config — without core-site.xml + HADOOP_CLASSPATH, CREATE SCHEMA fails with ClassNotFoundException: S3AFileSystem.

Verified

Ran the full slice locally end-to-end: legacy Hive table created (Parquet on s3a://warehouse/hive/...), queried (5 rows), migrated to Iceberg via CTAS, counts (5=5) and totals (256.49=256.49) matched. Base catalog dir confirmed untouched (no stub).

🤖 Generated with Claude Code