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The Site job fails when the data file is out of date or a page asks for a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

@@ -16,35 +16,6 @@ struct KeyHelp {
     const char* action;
 };
 
-namespace help {
-
-// Lists that several screens share.
-inline void list(std::vector<KeyHelp>& out, const char* enter = "open") {
-    out.push_back({"; .", "up, down"});
-    out.push_back({"Enter", enter});
-}
-inline void dialog(std::vector<KeyHelp>& out) {
-    out.push_back({", /", "the other answer"});
-    out.push_back({"Enter", "choose it"});
-    out.push_back({"`", "cancel"});
-}
-inline void textEntry(std::vector<KeyHelp>& out, const char* enter = "save") {
-    out.push_back({"Enter", enter});
-    out.push_back({"`", "cancel"});
-    out.push_back({"Del", "delete backwards"});
-    out.push_back({"Fn , /", "move the cursor"});
-    out.push_back({"opt ' e", "an accent: \xC3\xA9"});
-}
-// What works on every screen: the end of every panel.
-inline void everywhere(std::vector<KeyHelp>& out) {
-    out.push_back({"Everywhere", nullptr});
-    out.push_back({"`", "back"});
-    out.push_back({"Fn `", "home, the Launcher"});
-    out.push_back({"; . , /", "arrows (Fn+ while typing)"});
-    out.push_back({"Fn h  ?", "these keys (? not typing)"});
-}
-
-}  // namespace help
 
 // The panel itself: what it lists, and how far it's scrolled. The keys it takes while open are the
 // arrows; any other key closes it, and none reaches the App.