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The Site job fails when the data file is out of date or a page asks for a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

@@ -34,3 +34,9 @@ One bar for each of the 13 Wi-Fi channels shows how busy it is: how many network
 ## Signal tracker
 
 Follows one network: its name, address and channel, then the signal in dBm in large type, a strength bar, and a graph of the recent readings, so you can walk towards the strongest signal. <kbd>m</kbd> turns audible clicks on and off. If the network is no longer heard the screen says `lost`. <kbd>`</kbd> (Back) returns to the list.
+
+## 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=["wifi-tools", "wifi-networks", "wifi-tracker"]) }}