fix(connect): WS port preflight aborts under set -e when port is free (#70)

`preflight_ws_port` called `port_in_use "$p"; local rc=$?` as a bare
statement. Under `set -euo pipefail`, `port_in_use` returns non-zero
precisely when the port is FREE (its `grep -q` finds no listener), so
`set -e` aborts the whole installer before `rc` is ever read — the
common, healthy case silently kills the run right after the `ss | grep`.

Capture the status in an errexit-exempt context so the rc=2 (no
ss/netstat) / rc!=0 (free) / rc=0 (in use) branches work as intended:

    local rc=0; port_in_use "$p" || rc=$?

Applied identically to all three env installers (mainnet-beta/devnet/testnet).

Author: armcconnell

scripts/connect-devnet.sh

@@ -427,7 +427,7 @@ preflight_ws_port() {
   ws_disabled && return 0                       # sink off -> nothing to bind
   local p; p="$(ws_port)"
   case "$p" in *[!0-9]*|'') return 0;; esac      # not a plain numeric port -> let the bridge validate WS_BIND
-  port_in_use "$p"; local rc=$?
+  local rc=0; port_in_use "$p" || rc=$?
   if [ "$rc" -eq 2 ]; then
     warn "Can't check whether TCP port $p is free (no ss/netstat installed); if it's in use the WS sink won't bind (the tunnel is unaffected)."
     return 0

scripts/connect-testnet.sh

@@ -422,7 +422,7 @@ preflight_ws_port() {
   ws_disabled && return 0                       # sink off -> nothing to bind
   local p; p="$(ws_port)"
   case "$p" in *[!0-9]*|'') return 0;; esac      # not a plain numeric port -> let the bridge validate WS_BIND
-  port_in_use "$p"; local rc=$?
+  local rc=0; port_in_use "$p" || rc=$?
   if [ "$rc" -eq 2 ]; then
     warn "Can't check whether TCP port $p is free (no ss/netstat installed); if it's in use the WS sink won't bind (the tunnel is unaffected)."
     return 0

scripts/connect.sh

@@ -422,7 +422,7 @@ preflight_ws_port() {
   ws_disabled && return 0                       # sink off -> nothing to bind
   local p; p="$(ws_port)"
   case "$p" in *[!0-9]*|'') return 0;; esac      # not a plain numeric port -> let the bridge validate WS_BIND
-  port_in_use "$p"; local rc=$?
+  local rc=0; port_in_use "$p" || rc=$?
   if [ "$rc" -eq 2 ]; then
     warn "Can't check whether TCP port $p is free (no ss/netstat installed); if it's in use the WS sink won't bind (the tunnel is unaffected)."
     return 0