debugger: defer probe pause handling until startup

Keep the initial --inspect-brk pause held until probe breakpoints are
bound and probe mode explicitly releases the target. This prevents the
generic pause handler from resuming user code before probes are ready.
Refs: https://github.com/nodejs/node/actions/runs/26482141780/job/77981519238
Signed-off-by: Kamat, Trivikram <16024985+trivikr@users.noreply.github.com>
Assisted-by: openai:gpt-5.5
PR-URL: #63608
Refs: https://github.com/nodejs/node/actions/runs/26482141780/job/77981519238
Reviewed-By: Daijiro Wachi <daijiro.wachi@gmail.com>

Author: trivikr

lib/internal/debugger/inspect_probe.js

@@ -624,6 +624,10 @@ class ProbeInspectorSession {
 
 asynchandlePaused(params){
 if(this.finished){return;}
+// Ignore pauses that arrive before breakpoint setup is complete. Once
+// startup is marked complete, `Runtime.runIfWaitingForDebugger` may surface
+// the initial --inspect-brk pause, which the normal resume path handles.
+if(!this.started){return;}
 
 consthitBreakpoints=params.hitBreakpoints;
 if(hitBreakpoints===undefined||hitBreakpoints.length===0){
@@ -1025,5 +1029,6 @@ async function runProbeMode(stdout, probeOptions) {
 
 module.exports={
  parseProbeTokens,
+ ProbeInspectorSession,
  runProbeMode,
 };

test/parallel/test-debugger-probe-startup-pause.js

@@ -0,0 +1,32 @@
+// Flags: --expose-internals
+// This tests that probe mode ignores pauses until startup has finished binding
+// breakpoints.
+'use strict';
+
+constcommon=require('../common');
+common.skipIfInspectorDisabled();
+
+constassert=require('assert');
+const{ ProbeInspectorSession }=require('internal/debugger/inspect_probe');
+
+constsession=newProbeInspectorSession({
+probes: [],
+});
+
+constcdpCalls=[];
+session.client={
+callMethod: common.mustCall(async(method)=>{
+cdpCalls.push(method);
+}),
+};
+
+asyncfunctiontestStartupPauseHandling(){
+awaitsession.handlePaused({});
+assert.deepStrictEqual(cdpCalls,[]);
+
+session.started=true;
+awaitsession.handlePaused({});
+assert.deepStrictEqual(cdpCalls,['Debugger.resume']);
+}
+
+testStartupPauseHandling().then(common.mustCall());