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The Site job fails when the data file is out of date or a page asks for a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

@@ -1,3 +1,4 @@
+#include "app_keys.h"
 #include "storage_app.h"
 
 #include <Arduino.h>
@@ -279,26 +280,13 @@ void StorageApp::help(std::vector<KeyHelp>& out) const {
         case View::Maintenance: return maintenance_.help(out);
         case View::Editor: return noteEditor_.help(out);
         case View::Viewer: return viewer_.help(out);
-        case View::Details:
-            out.push_back({"; .", "scroll"});
-            out.push_back({"Enter", "back to the folder"});
-            return;
+        case View::Details: return keys::add(out, keys::kStorageDetails);
         default: break;
     }
-    if (dialog_) return help::dialog(out);
-    if (wantList_ || wait_ != Wait::None) return (void)out.push_back({"`", "stop the copy or the delete"});
-    if (view_ == View::Name) return help::textEntry(out, renaming_ ? "rename it" : "make the folder");
-    help::list(out, "open the folder or the file");
-    out.push_back({", /", "a page up, down"});
-    out.push_back({"c  x", "copy, cut"});
-    out.push_back({"v", "paste here"});
-    out.push_back({"r", "rename"});
-    out.push_back({"d  Del", "delete, after asking"});
-    out.push_back({"n", "a new folder"});
-    out.push_back({"i", "details: size, date, type"});
-    out.push_back({"s", "sort: name, date, size"});
-    out.push_back({"m", "Maintenance: clean-up, erase"});
-    out.push_back({"`", "the folder above"});
+    if (dialog_) return keys::add(out, keys::kDialog);
+    if (wantList_ || wait_ != Wait::None) return keys::add(out, keys::kStorageBusy);
+    if (view_ == View::Name) return keys::add(out, keys::kStorageName);
+    keys::add(out, keys::kStorage);
 }
 
 const char* StorageApp::helpTitle() const {