One firmware: the Debug Console in every build, off until switched on, with the device's own token

There is no Debug Build any more (ADR 0010, issue #68, Q188 to Q195). The
console and the test commands are compiled into every firmware. It listens
only while Settings > Debug Console is on, which isn't the default; off,
neither its task nor its 4 KB ring exists. The token is made by the device
and shown on that page; a client proves it knows it by answering a challenge
with an HMAC, so it never crosses the network, and five wrong answers close
the console for a minute. DBG in the Status Bar while it listens.

Over USB serial only: debug on, debug token <value>, debug token new.
scripts/flash.sh --debug uses them to set a device up with the developer's
token. scripts/rdbg.py takes the token from -t, $RORO_DEBUG_TOKEN or the
file, answers the challenge, and fetches a release's ELF to decode a crash.

Gone: the cardputer-adv-debug environment, RORO_DEBUG, the +debug version,
scripts/debug_flags.py, update install ... force, and the rule that a Debug
Build doesn't install releases. Old clients and old firmwares don't talk to
each other.

Against the builds it replaces: 30 KB more flash and 88 bytes more static
RAM than the release, 4 KB less RAM than the Debug Build. 468 host tests.
Checked on the device: off by default, login, the pause after wrong tokens,
Safe Mode with the console, the setting surviving an update, debug off.

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

src/apps/settings_app.cpp

@@ -34,6 +34,9 @@ bool SettingsApp::onKey(const KeyEvent& e) {
         case Page::Firmware:
             if (!firmwarePage_.onKey(e)) page_ = Page::Menu;
             return true;
+        case Page::Debug:
+            if (!debugPage_.onKey(e)) page_ = Page::Menu;
+            return true;
     }
     return false;
 }
@@ -75,6 +78,10 @@ bool SettingsApp::onMenuKey(const KeyEvent& e) {
                     page_ = Page::Firmware;
                     firmwarePage_.enter();
                     break;
+                case Row::DebugConsole:
+                    page_ = Page::Debug;
+                    debugPage_.enter();
+                    break;
                 default: page_ = Page::About; break;
             }
             break;
@@ -124,7 +131,7 @@ bool SettingsApp::onAboutKey(const KeyEvent& e) {
 
 void SettingsApp::update(uint32_t nowMs) {
     // Live values on About and Firmware.
-    bool live = page_ == Page::About || page_ == Page::Firmware ||
+    bool live = page_ == Page::About || page_ == Page::Firmware || page_ == Page::Debug ||
                 (page_ == Page::Wifi && wifiPage_.live());
     if (live && nowMs - lastRefreshMs_ >= 500) {
         lastRefreshMs_ = nowMs;
@@ -184,6 +191,7 @@ void SettingsApp::draw(Canvas& c) {
         case Page::About: widgets::textLines(c, aboutLines(), 0, area); break;
         case Page::Wifi: wifiPage_.draw(c); break;
         case Page::Firmware: firmwarePage_.draw(c); break;
+        case Page::Debug: debugPage_.draw(c); break;
     }
 }