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

site/content/dev/debug/_index.md

@@ -1,5 +1,5 @@
 +++
-title = "Debug Builds and the Debug Console"
+title = "The Debug Console"
 description = "A firmware you can drive from your desk: its console over Wi-Fi, its screen as a PNG, its SD card, its crash dumps, and a way back when an update goes wrong."
 template = "guide-index.html"
 page_template = "guide-page.html"
@@ -10,13 +10,13 @@ weight = 1
 eyebrow = "Developer docs"
 +++
 
-A **Debug Build** is the same firmware plus a **Debug Console**: the serial console, over Wi-Fi, behind a token. It is the most useful thing in the project. With it you can:
+The **Debug Console** is the serial console, over Wi-Fi, for whoever holds the device's token. It is in **every firmware**, switched off until you switch it on, and it is the most useful thing in the project. With it you can:
 
 - **see everything the device prints**, boot messages included, without a cable;
 - **run every serial command** from your desk;
 - **press keys** and **take screenshots**, so a UI change can be tested and looked at remotely;
 - **copy files** to and from the SD card;
 - **read crash reports and fetch core dumps**, decoded against the exact build that crashed;
-- **update the firmware** over the same Wi-Fi, and know that a bad update rolls back to a build that still has the console.
+- **update the firmware** over the same Wi-Fi, and know that a bad update rolls back by itself.
 
-Start with [Debug Builds](/dev/debug/debug-builds/) to put one on a device, then [the Debug Console](/dev/debug/console/). The rest are what you can do with it.
+Start with [Switch the console on](/dev/debug/switch-it-on/), then [the Debug Console](/dev/debug/console/). The rest are what you can do with it.