fix: write crash report on loop detection and add recovery hints

Address review feedback:
- Move exit handler registration to after all CLI validation passes so
  user config errors (bad port, auth, bind) are not counted as crashes.
- Write a crash-report.json with timestamps when the hard crash limit
  is reached.
- Add recovery instructions to the CrashLoopError message (delete
  the history file or wait for the window to expire).

Co-authored-by: Cursor <cursoragent@cursor.com>

src/cli/gateway-cli/crash-loop-guard.ts

@@ -99,7 +99,9 @@ export class CrashLoopError extends Error {
     super(
       `CRASH LOOP DETECTED: ${count} crashes in the last ${windowMinutes} minutes. ` +
         `The gateway will not restart automatically. ` +
-        `Fix the root cause, then run the gateway manually.`,
+        `Fix the root cause, then run the gateway manually. ` +
+        `To reset the crash counter immediately, delete the gateway-crash-history.json ` +
+        `file in the state directory, or wait ${windowMinutes} minutes for it to expire.`,
     );
     this.name = "CrashLoopError";
     this.recentCrashCount = count;
@@ -118,6 +120,27 @@ export async function applyCrashLoopGuard(deps: CrashLoopGuardDeps): Promise<voi
   const recentCrashes = history.crashes.filter((t) => t > cutoff);
 
   if (recentCrashes.length >= MAX_CRASHES) {
+    const reportPath = path.join(deps.stateDir, "crash-report.json");
+    try {
+      fs.mkdirSync(path.dirname(reportPath), { recursive: true });
+      fs.writeFileSync(
+        reportPath,
+        JSON.stringify(
+          {
+            detectedAt: new Date(now).toISOString(),
+            recentCrashCount: recentCrashes.length,
+            windowMinutes: CRASH_WINDOW_MS / 60_000,
+            crashTimestamps: recentCrashes.map((t) => new Date(t).toISOString()),
+          },
+          null,
+          2,
+        ),
+        "utf-8",
+      );
+      deps.logger.error(`Crash report written to ${reportPath}`);
+    } catch {
+      // best-effort
+    }
     throw new CrashLoopError(recentCrashes.length, CRASH_WINDOW_MS / 60_000);
   }
 

src/cli/gateway-cli/run.ts

@@ -3,7 +3,6 @@ import { readSecretFromFile } from "../../acp/secret-file.js";
 import fs from "node:fs";
 import path from "node:path";
 import type { GatewayAuthMode, GatewayTailscaleMode } from "../../config/config.js";
-import type { GatewayWsLogStyle } from "../../gateway/ws-logging.js";
 import {
   CONFIG_PATH,
   loadConfig,
@@ -14,6 +13,7 @@ import {
 import { hasConfiguredSecretInput } from "../../config/types.secrets.js";
 import { resolveGatewayAuth } from "../../gateway/auth.js";
 import { startGatewayServer } from "../../gateway/server.js";
+import type { GatewayWsLogStyle } from "../../gateway/ws-logging.js";
 import { setGatewayWsLogStyle } from "../../gateway/ws-logging.js";
 import { setVerbose } from "../../globals.js";
 import { GatewayLockError } from "../../infra/gateway-lock.js";