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The Site job fails when the data file is out of date or a page asks for a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

src/apps/irc_app.cpp

@@ -1,3 +1,4 @@
+#include "app_keys.h"
 #include "irc_app.h"
 
 #include "ui/fonts.h"
@@ -300,29 +301,9 @@ void IrcApp::drawChat(Canvas& c) {
 }
 
 void IrcApp::help(std::vector<KeyHelp>& out) const {
-    if (page_ == Page::Settings) {
-        if (editing_) return help::textEntry(out, "keep it");
-        help::list(out, "edit, switch, or save");
-        out.push_back({"`", "leave without saving"});
-        return;
-    }
-    out.push_back({"Enter", "send the line"});
-    out.push_back({"Tab", "the next buffer"});
-    out.push_back({"Alt ; .", "scroll back, forward"});
-    out.push_back({"Fn ; .", "lines you sent before"});
-    out.push_back({"Fn , /", "move the cursor"});
-    out.push_back({"Del", "delete backwards"});
-    out.push_back({"/settings", "server, nick, passwords"});
-    out.push_back({"/join #x", "join a channel"});
-    out.push_back({"/part", "leave it"});
-    out.push_back({"/msg nick", "a private chat"});
-    out.push_back({"/me", "an action"});
-    out.push_back({"/nick", "change your nick"});
-    out.push_back({"/topic", "see or set the topic"});
-    out.push_back({"/names", "who is there"});
-    out.push_back({"/quit", "disconnect, and stay so"});
-    out.push_back({"/raw", "a line as it is"});
-    out.push_back({"`", "leave: IRC stays connected"});
+    if (page_ == Page::Chat) return keys::add(out, keys::kIrc);
+    if (editing_) return keys::add(out, keys::kIrcField);
+    keys::add(out, keys::kIrcSettings);
 }
 
 const char* IrcApp::helpTitle() const {