Debug Console: the listener is checked and retried, and debug off <seconds> comes back by itself

The framework's server begin() fails without a word: the console's task now
asks whether it listens, says so, and tries again. `debug off <seconds>`
closes the console and reopens it after the pause, which is the only way to
test its closing and reopening from afar.

Checked on the device: 25 closings and reopenings, each back a second after
the pause. Free heap dips about 270 bytes for each connection the device
closes and is all back two minutes later (TCP keeps a closed connection that
long): not a leak.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EhqxQ49eCju4CzKYNjZzwT

src/main.cpp

@@ -564,7 +564,7 @@ static const char* const kHelp =
     "install <path.ota>   Update from SD\n"
     "update check | list | status | install <tag>   the project's releases on Gitea\n"
     "sd card | sd list | cat <path> | log <text> | burst | sound on|off | short | normal\n"
-    "debug status | debug off   the Debug Console over Wi-Fi (Settings > Debug Console)\n"
+    "debug status | debug off [seconds]   the Debug Console over Wi-Fi (Settings > Debug Console); with seconds, it comes back\n"
     "debug on | debug token <16 to 64 characters> | debug token new   (USB serial only) switch it on, set its token\n"
     "crash abort|wdt   crash on purpose (to test crash reports and Safe Mode)\n"
     "wifi ip ... try <seconds> | wifi ip keep   a trial IP setting: back to the previous one unless kept\n"
@@ -585,6 +585,16 @@ static bool safeModeCommand(const String& line) {
            line == "wifi status" || line.startsWith("wifi add ") || line.startsWith("debug ");
 }
 
+// `debug off <seconds>`: the console closes and comes back by itself. It can't open itself wider
+// that way (it was on, with the same token), and it's how its closing and reopening is tested from afar.
+static bool debugResumes = false;
+static uint32_t debugResumeMs = 0;
+static void debugResumeStep() {
+    if (!debugResumes || static_cast<int32_t>(millis() - debugResumeMs) < 0) return;
+    debugResumes = false;
+    settings.setBool(Setting::DebugConsole, true);
+}
+
 // `debug ...`: the Debug Console's switch and token (ADR 0010). Switching it on and setting its token
 // are for USB serial only (Q192): whoever holds the cable holds the device anyway, and the console
 // can't be used to open itself wider. The token is never printed.
@@ -595,6 +605,13 @@ static void debugCommand(const String& args, bool fromSerial) {
     } else if (args == "off") {
         settings.setBool(Setting::DebugConsole, false);
         console.println("debug: off");
+    } else if (args.startsWith("off ")) {  // debug off <seconds>: a pause, then on again as it was
+        uint32_t seconds = constrain(args.substring(4).toInt(), 1, 600);
+        if (!settings.getBool(Setting::DebugConsole)) return (void)console.println("debug: it is off");
+        settings.setBool(Setting::DebugConsole, false);
+        debugResumeMs = millis() + seconds * 1000;
+        debugResumes = true;
+        console.printf("debug: off for %lu s\n", (unsigned long)seconds);
     } else if (!fromSerial) {
         console.println("debug: over USB serial only (or Settings > Debug Console)");
     } else if (args == "on") {
@@ -607,7 +624,7 @@ static void debugCommand(const String& args, bool fromSerial) {
         std::string token = debug::tidyToken(args.substring(6).c_str());
         bool ok = debug::validToken(token) && settings.setString(Setting::DebugToken, token);
         console.println(ok ? "debug: token set" : "debug: a token is 16 to 64 characters");
-    } else console.println("debug: status | off | on | token <16 to 64 characters> | token new");
+    } else console.println("debug: status | off [seconds] | on | token <16 to 64 characters> | token new");
 }
 
 static void runCommand(String line, bool fromSerial = false) {
@@ -1004,6 +1021,7 @@ static void remoteCommands() {
         console.printf("> %s\n", remote.c_str());  // so the transcript reads the same on both ends
         runCommand(remote.c_str());
     }
+    debugResumeStep();
     for (std::string alert; debugConsole->takeAlert(alert);)
         bus.publish(Event::withText(EventType::Notification, alert.c_str(), static_cast<int32_t>(NotificationLevel::Warning)));
 }