Keys: one table file for the device's help panel and the website's key tables (#72)

Every screen's keys are constant tables in lib/core/src/app_keys.h (52 of
them, each under an `// id: Title` comment). An App's help() picks the table
of the state it is in. site/tools/gen_dev_docs.py reads the same file and
writes site/data/keys.toml; the `keys` shortcode shows a screen's tables on
its guide page, and /guide/keys/ shows all of them.

The Site job fails when the data file is out of date or a page asks for a
table that doesn't exist, and now also runs when app_keys.h changes. A key
added to an App shows up on the website without anyone editing a page.

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

site/content/guide/irc.md

@@ -49,3 +49,9 @@ Every buffer is logged to the SD card, one file per day, under `/irc`. Logs stop
 
 - IRC **pauses** while Wi-Fi is monitoring (the Status Bar shows `MON`) and while the device **installs an update**. It reconnects and rejoins its channels afterwards; the App says `paused` in the meantime.
 - A secure connection costs memory: IRC's takes about 40 KB of the 107 KB the device has, and an update's download needs about 52 KB more. That is why IRC steps aside for an update, and why the daily update check waits for IRC to be disconnected (see [Updates](/guide/updates/)).
+
+## The keys, as the device lists them
+
+What <kbd>Fn</kbd> + <kbd>h</kbd> shows on these screens. These tables are generated from the firmware's own lists, so they are always the current ones.
+
+{{ keys(scopes=["irc", "irc-settings", "irc-field"]) }}