2V1-b/c: PythonNetworkStream phases, AccountConnector and the net module

Port PythonNetworkStream with its HandShake/Login/Select/Loading/Offline
phases, AccountConnector and PythonNetworkStreamModule verbatim; the net
stub goes. PythonBoot creates the network stream, account connector,
player, flying manager and effect manager like CPythonApplication, and
app.Create/Process drive CNetworkDevice and both connectors.

Packet.h long fields become 32-bit LONG; port.packet checks 38
login/select/loading packet sizes against wire_classic.h. Unported units
in the link closure live under platform/pending/ as stand-ins. The macOS
gate now builds all and finds iconv.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

script/port_gate.sh

@@ -33,7 +33,8 @@ for p in "${PLATFORMS[@]}"; do
 	BUILD_EXTRA=()
 	case "$p" in
 	macos)
-		BUILD_EXTRA=(--target port_common_test --target port_eterpack_test)
+		# Every port test target, so the ctest run below never meets a test the gate did not build.
+		BUILD_EXTRA=(--target all)
 		run macos "$OUT/macos" "${PORT_ONLY[@]}" -DBUILD_TESTING=ON
 		last=$((${#RESULTS[@]} - 1))
 		if [[ "${RESULTS[$last]}" == *PASS ]] && ! ctest --test-dir "$OUT/macos" -R '^port\.' --output-on-failure >>"$OUT/macos.log" 2>&1; then