… /pods

The list_pods_unified handler was creating 2N Docker connections and
doing 2N inspect_container calls for N running pods: one set from
get_pod_api_port (via fetch_agent_status_for_pod) and another from
get_pod_forwarded_ports, both inspecting the same container.

Replace these with a single shared bollard::Docker connection (wrapped
in Arc for the spawned tasks) and a new inspect_pod_ports() function
that does one inspect_container call per pod and extracts both the
pod-api host port and forwarded ports from the result.

This halves the number of Docker socket round-trips per /pods request
and eliminates repeated connection setup overhead.

Assisted-by: OpenCode (Claude Opus 4)