Help: Fn+h lists the keys of the screen you're on, and no screen names its keys any more (#69)

Fn+h on any screen, text fields included, and ? outside Text Entry, open a
panel over the content area: the screen's own keys, then the ones that work
everywhere. Every App declares its keys for the state it is in (pages,
viewers, dialogs and text fields answer for themselves); the App manager
opens the panel and takes every key while it is open.

About 30 hint lines are gone, from every App. What stays on a screen is
state. The first-start Setup keeps its hints and teaches the key; a device
set up before gets one Toast, once. The guide and the FAQ open with it.
`key help` over the consoles.

476 host tests (8 new). Checked on the device with key help and screenshots:
the Launcher, all nine Apps and several of their states. 8.5 KB of flash and
40 bytes of static RAM. Decisions Q196 to Q203 in docs/milestones/U1.md.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EhqxQ49eCju4CzKYNjZzwT

src/apps/firmware_page.cpp

@@ -63,9 +63,9 @@ std::string FirmwarePage::latestText(bool& warn) const {
     release::Release r;
     if (g.status() == GiteaReleases::Status::Failed && !g.latest(r)) {
         warn = true;
-        return "failed: Enter retries";
+        return "the check failed";
     }
-    if (!g.latest(r)) return "Enter: check";
+    if (!g.latest(r)) return "not checked yet";
     return r.tag + (release::isNewer(r, update_.runningVersion()) ? " (new)" : " (current)");
 }
 
@@ -202,7 +202,7 @@ void FirmwarePage::drawRelease(Canvas& c) {
     c.setFont(&fonts::small);
     c.setTextDatum(top_left);
     c.setTextColor(theme::kMuted);
-    c.drawString(ok ? "Enter: install   c: check again" : (why + "   c: check").c_str(), 4, area.y + area.h - 9);
+    if (!ok) c.drawString(why.c_str(), 4, area.y + area.h - 9);  // why it can't be installed from here
 }
 
 void FirmwarePage::drawOlder(Canvas& c) {
@@ -232,9 +232,29 @@ void FirmwarePage::drawOlder(Canvas& c) {
             return r.tag + (r.tag == running ? "  (running)" : release::versionNewer(r.tag, running) ? "  (new)" : "");
         },
         [&](int i) { return olderReleases_[i].date(); });
-    c.setFont(&fonts::small);
-    c.setTextColor(theme::kMuted);
-    c.drawString("Enter: details   c: look again", 4, area.y + area.h - 9);
+}
+
+void FirmwarePage::help(std::vector<KeyHelp>& out) const {
+    if (confirm_) return help::dialog(out);
+    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;
+    }
+}
+
+const char* FirmwarePage::helpTitle() const {
+    return view_ == View::Release ? "A release" : view_ == View::Older ? "Older releases" : "Firmware";
 }
 
 void FirmwarePage::drawMain(Canvas& c) {