Schema and catalog introspection over JDBC `DatabaseMetaData`, returning
normalized Clojure data. Each function takes a db spec or datasource (anything
`next.jdbc/get-connection` accepts) and, optionally, a table name.

Table and schema names are accepted as strings or keywords. Results use
keyword names so they compose with the rest of psql-clj.

Operational controls exposed by pgjdbc's `PGConnection` and the JDBC
connection: the backend process id, query cancellation, server parameter
statuses, the default fetch size, the transaction autosave mode, and a helper
to set the per-session statement timeout.

Each function accepts a `java.sql.Connection` (the value `next.jdbc` hands you
inside `with-open`/`on-connection`) and unwraps the pgjdbc `PGConnection` as
needed.

PostgreSQL COPY helpers that use pgjdbc's CopyManager.

COPY runs on a java.sql.Connection. The caller owns the connection and must keep it open for the COPY operation.

Use PostgreSQL from Clojure with connection parameter defaults from PGDATABASE, PGHOST, PGPORT, and PGUSER.
Read the password from ~/.pgpass when it is available.

PostgreSQL large-object (`lo`) helpers over pgjdbc's `LargeObjectManager`.

Large objects are stored in `pg_largeobject` and addressed by an OID. Every
operation must run inside a transaction (set autocommit off, e.g. with
`next.jdbc/with-transaction`); pgjdbc raises otherwise. Each function accepts
the `java.sql.Connection` for manager operations, or an open `LargeObject` for
read/write/seek. The caller owns the connection and transaction lifecycle.

PostgreSQL LISTEN/NOTIFY helpers that use pgjdbc.

Use a dedicated open connection for listening. pgjdbc surfaces notifications
only when a query is sent or get-notifications is called. A blocking poll
prevents other statements from using the connection until the poll returns.

Match ~/.pgpass passwords to db specs.

Hikari connection pool.

PostgreSQL streaming replication over pgjdbc: log sequence numbers (LSNs),
replication-slot management, and logical decoding streams.

A replication connection is a special connection opened with the `replication`
property set; `replication-spec` adds the required properties to a db spec.
The server must run with `wal_level = logical` (and enough `max_wal_senders` /
`max_replication_slots`) for logical replication.

Resolve pgjdbc service definitions to psql-clj database specs.

Extend next.jdbc's SettableParameter and ReadableColumn protocols so that
PGobject (json/jsonb/enum), SQL arrays, and inet values move between Clojure
data and PostgreSQL without manual wrapping.

The map->parameter / vec->parameter / num->parameter multimethods are the
extension point: companion artifacts, such as psql-clj-gis, add methods for
their SQL types without this namespace depending on them.