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The Site job fails when the data file is out of date or a page asks for a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/updates.md

@@ -42,3 +42,9 @@ The connection to the project's server is checked against the two root certifica
 ## For developers
 
 Updates can also be pushed from a PC over Wi-Fi, with `scripts/flash.sh --ota <ip>`, or put on the card with `scripts/sd_put.sh`: see the [README](https://git.twis.la/twisla/roro9stack#firmware-updates-over-wi-fi-ota). The firmware's console can be reached over Wi-Fi too: see [The Debug Console](/dev/debug/).
+
+## 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=["firmware", "firmware-release", "firmware-older"]) }}