bridge: fix exponential reconnect (OOM) + add dataref resolve probe

The X-Plane socket fired both 'error' and 'close' on a failed connect, each
scheduling a reconnect — so attempts doubled every cycle, leaking sockets/timers
until the process OOMed (~3 min with the sim down). Guard onDown so each socket
schedules exactly one reconnect (and tear the dead socket down).

Also log a one-shot resolve-probe (GET /datarefs?filter[name]=airspeed…) on
connect so a Web-API version/format mismatch is visible in the log.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

server/bridge.js

@@ -79,6 +79,15 @@ async function fetchAllByName(resource, names) {
 
 // ---- X-Plane connection ---------------------------------------------------
 async function resolveIds() {
+  // one-shot diagnostic: probe a universal dataref so the log shows the API's
+  // real response shape (helps when a version/format mismatch yields 0 matches).
+  try {
+    const probe = 'sim/cockpit2/gauges/indicators/airspeed_kts_pilot';
+    const u = `${REST}/datarefs?filter[name]=${encodeURIComponent(probe)}`;
+    const r = await fetch(u, { headers: { Accept: 'application/json' } });
+    const txt = await r.text();
+    log(`resolve-probe: GET ${u} -> HTTP ${r.status}; body ${txt.slice(0, 160)}`);
+  } catch (e) { log(`resolve-probe failed: ${e.message}`); }
   const drefNames = Object.values(DATAREFS);
   const cmdNames = Object.values(COMMANDS);
   state.drefNameToId = await fetchAllByName('datarefs', [
@@ -146,11 +155,18 @@ function connectXPlane() {
     }
   });
 
+  // 'error' and 'close' both fire on a failed socket — guard so each socket
+  // schedules exactly ONE reconnect (otherwise attempts double every cycle and
+  // the process leaks sockets/timers until it OOMs).
+  let downHandled = false;
   const onDown = (why) => {
+    if (downHandled) return;
+    downHandled = true;
     if (state.xpConnected) log(`X-Plane disconnected (${why})`);
     state.xpConnected = false;
     broadcast({ type: 'status', xpConnected: false });
     if (state.xpSocket === sock) state.xpSocket = null;
+    try { sock.removeAllListeners(); sock.terminate?.(); } catch {}
     setTimeout(connectXPlane, 3000);
   };
   sock.on('close', () => onDown('close'));