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The Site job fails when the data file is out of date or a page asks for a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

lib/core/src/app_manager.cpp

@@ -1,5 +1,7 @@
 #include "app_manager.h"
 
+#include "app_keys.h"
+
 #include <cstring>
 
 namespace roro {
@@ -60,7 +62,8 @@ void AppManager::handleKey(const KeyEvent& event) {
     if (event.key == Key::Help) {
         std::vector<KeyHelp> rows;
         foreground_->help(rows);
-        help::everywhere(rows);
+        rows.push_back({"Everywhere", nullptr});
+        keys::add(rows, keys::kEverywhere);
         const char* scope = foreground_->helpTitle();
         const char* app = foregroundTitle();
         help_.open(scope ? scope : app ? app : "Launcher", std::move(rows));