feat: bridge relay proxy port 3000 to 8091

**Motivations :**
- keep nginx configuration unchanged while exposing sdk_relay via relay235.4nkweb.com

**Modifications :**
- add socat proxy management to start-dev.sh lifecycle
- include proxy status reporting and pid tracking

**Page affectées :**
- start-dev.sh

start-dev.sh

@@ -14,6 +14,8 @@ RELAY_DIR="${ROOT_DIR}/sdk_relay"
 RELAY_BIN="${RELAY_DIR}/target/release/sdk_relay"
 RELAY_PID_FILE="${LOG_DIR}/sdk_relay.pid"
 RELAY_LOG_FILE="${LOG_DIR}/sdk_relay.log"
+PROXY_PORT=3000
+PROXY_PID_FILE="${LOG_DIR}/sdk_relay.proxy.pid"
 
 mkdir -p "${LOG_DIR}"
 
@@ -89,6 +91,16 @@ start_relay() {
   echo "[start] sdk_relay PID $(cat "${RELAY_PID_FILE}")"
 }
 
+start_proxy() {
+  stop_proxy >/dev/null 2>&1 || true
+  stop_port "${PROXY_PORT}" || true
+
+  echo "[start] Launching relay TCP proxy ${PROXY_PORT}->${RELAY_PORT}"
+  socat TCP-LISTEN:${PROXY_PORT},reuseaddr,fork TCP:127.0.0.1:${RELAY_PORT} > "${LOG_DIR}/sdk_relay.proxy.log" 2>&1 &
+  echo $! > "${PROXY_PID_FILE}"
+  echo "[start] proxy PID $(cat "${PROXY_PID_FILE}")"
+}
+
 stop_front() {
   stop_pid_file "${FRONT_PID_FILE}"
   stop_port "${FRONT_PORT}" || true
@@ -101,6 +113,12 @@ stop_relay() {
   echo "[stop] sdk_relay stopped"
 }
 
+stop_proxy() {
+  stop_pid_file "${PROXY_PID_FILE}"
+  stop_port "${PROXY_PORT}" || true
+  echo "[stop] relay proxy stopped"
+}
+
 status_service() {
   local name="$1"
   local pid_file="$2"
@@ -130,10 +148,12 @@ command_all() {
   case "${action}" in
     start)
       start_relay
+      start_proxy
       start_front
       ;;
     stop)
       stop_front
+      stop_proxy
       stop_relay
       ;;
     restart)
@@ -142,6 +162,7 @@ command_all() {
       ;;
     status)
       status_service "sdk_relay" "${RELAY_PID_FILE}" "${RELAY_PORT}"
+      status_service "relay proxy" "${PROXY_PID_FILE}" "${PROXY_PORT}"
       status_service "ihm_client" "${FRONT_PID_FILE}" "${FRONT_PORT}"
       ;;
     *)