Multiple Connections, either all at the same time or one at a time, in one script

[HenryNebula]

Legacy issue: baztian/jaydebeapi#56

Tier: P0 — shared-bug

Multiple connections failing after the first is a JPype/JVM resource management bug. Our codebase still uses JPype and has its own connect() implementation — the same JVM-level connection cleanup issues could still exist.

[HenryNebula]

Triage verification: #98

The upstream Py4J-era bug (baztian/jaydebeapi#56) about getConnection overload mismatches does not reproduce in the JPype-based implementation. Sequential and simultaneous connections work correctly — verified with HSQLDB integration tests. All CI checks pass.