pg-ephemeral 0.5.1

Added

• Set PostgreSQL server parameters per instance via an
  [instances.<name>.parameters] table in database.toml, passed to the
  server as -c <name>=<value> flags at launch (e.g.
  shared_preload_libraries, work_mem, log_statement). Parameters are
  folded into the seed cache key, so changing one re-runs the affected
  seeds. The Rust API exposes the same via the
  Definition::parameter(name, value) builder.
• pg-ephemeral bin -- <tool> [args…] runs a tool from the instance image
  against the host working directory without booting PostgreSQL: the current
  working directory is bind-mounted into the container at the same path, the
  tool runs as the container entrypoint, and its stdout/stderr stream to the
  terminal. Intended for running the image's version-pinned tooling
  (pg_dump, pg_verifybackup, pg_waldump, …) on host files. Host stdin is
  forwarded and a PTY is attached when run from a terminal. The host PG*
  environment is forwarded, so tools reach the same routable database the shell
  is configured for (path-valued vars like PGSSLROOTCERT resolve only for
  files inside the bind-mounted working directory). What bin does not yet do
  is reach a host-local (localhost) database tunnel — a planned follow-up.
  Select the image with --instance / --image.

Changed

• Connecting to the ephemeral database no longer reads process environment
  variables; ambient PG* variables can no longer interfere with connection
  setup.
• Raised minimum supported Rust version to 1.95.