fix: release gateway lock before process.exit in run-loop

process.exit() called from inside an async IIFE bypasses the outer
try/finally block that releases the gateway lock. This leaves a stale
lock file pointing to a zombie PID, preventing the spawned child or
systemctl restart from acquiring the lock. Release the lock explicitly
before calling exit in both the restart-spawned and stop code paths.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/cli/gateway-cli/run-loop.ts

@@ -90,6 +90,7 @@ export async function runGatewayLoop(params: {
                 ? `spawned pid ${respawn.pid ?? "unknown"}`
                 : "supervisor restart";
             gatewayLog.info(`restart mode: full process restart (${modeLabel})`);
+            await lock?.release();
             cleanupSignals();
             params.runtime.exit(0);
           } else {
@@ -104,6 +105,7 @@ export async function runGatewayLoop(params: {
             restartResolver?.();
           }
         } else {
+          await lock?.release();
           cleanupSignals();
           params.runtime.exit(0);
         }