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The Site job fails when the data file is out of date or a page asks for a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

@@ -1,3 +1,4 @@
+#include "app_keys.h"
 #include "firmware_page.h"
 
 #include <SD.h>
@@ -235,21 +236,11 @@ void FirmwarePage::drawOlder(Canvas& c) {
 }
 
 void FirmwarePage::help(std::vector<KeyHelp>& out) const {
-    if (confirm_) return help::dialog(out);
+    if (confirm_) return keys::add(out, keys::kDialog);
     switch (view_) {
-        case View::Main:
-            help::list(out, "check, open, or install");
-            out.push_back({"c", "look for a newer release"});
-            break;
-        case View::Release:
-            out.push_back({"; .", "scroll"});
-            out.push_back({"Enter", "install it"});
-            out.push_back({"c", "check again"});
-            break;
-        case View::Older:
-            help::list(out, "its details");
-            out.push_back({"c", "read the list again"});
-            break;
+        case View::Main: keys::add(out, keys::kFirmware); break;
+        case View::Release: keys::add(out, keys::kFirmwareRelease); break;
+        case View::Older: keys::add(out, keys::kFirmwareOlder); break;
     }
 }