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/wifi_settings_page.cpp

@@ -413,7 +413,6 @@ void WifiSettingsPage::draw(Canvas& c) {
             c.setTextColor(theme::kMuted);
             c.drawString(editTitle_.c_str(), 4, area.y + 4);
             widgets::lineEditor(c, editor_, {4, area.y + 22, area.w - 8, 0});
-            c.drawString("Enter: save   `: cancel", 4, area.y + 44);
             break;
         }
 
@@ -427,7 +426,7 @@ void WifiSettingsPage::draw(Canvas& c) {
                 if (!n.ssid.empty()) found.push_back(n);
             if (scan_.count() != static_cast<int>(found.size())) scan_.setCount(static_cast<int>(found.size()));
             if (found.empty()) {
-                widgets::textLines(c, {"No networks found.", "", "`: back"}, 0, area);
+                widgets::textLines(c, {"No networks found."}, 0, area);
                 break;
             }
             widgets::list(
@@ -443,20 +442,55 @@ void WifiSettingsPage::draw(Canvas& c) {
             std::string title = view_ == View::Ssid ? "Hidden network name" : "Password for " + newSsid_;
             c.drawString(title.c_str(), 4, area.y + 4);
             widgets::lineEditor(c, editor_, {4, area.y + 22, area.w - 8, 0});
-            c.drawString(view_ == View::Ssid ? "Enter: next   `: cancel" : "Enter: save (empty = open)   `: cancel", 4,
-                         area.y + 44);
+            if (view_ == View::Password) c.drawString("Leave it empty for an open network.", 4, area.y + 44);
             break;
         }
     }
 }
 
+void WifiSettingsPage::help(std::vector<KeyHelp>& out) const {
+    if (forgetDialog_) return help::dialog(out);
+    switch (view_) {
+        case View::Main:
+            help::list(out, "open, or change");
+            out.push_back({", /", "switch Wi-Fi on or off"});
+            break;
+        case View::Servers:
+            help::list(out, "edit");
+            out.push_back({", /", "Always use my DNS: on, off"});
+            break;
+        case View::Network:
+            help::list(out, "edit, or forget");
+            out.push_back({", /", "Automatic or Fixed"});
+            break;
+        case View::Details: out.push_back({"Enter", "back"}); break;
+        case View::Scan: help::list(out, "choose this network"); break;
+        case View::Ssid: help::textEntry(out, "next: the password"); break;
+        case View::Password:
+        case View::Edit: help::textEntry(out); break;
+    }
+}
+
+const char* WifiSettingsPage::helpTitle() const {
+    switch (view_) {
+        case View::Servers: return "DNS and NTP";
+        case View::Network: return "A saved network";
+        case View::Details: return "Wi-Fi status";
+        case View::Scan: return "Add a network";
+        case View::Ssid: return "Hidden network name";
+        case View::Password: return "Wi-Fi password";
+        case View::Edit: return "Wi-Fi: a field";
+        default: return "Wi-Fi";
+    }
+}
+
 // What the device is using and where each part came from (Q113).
 void WifiSettingsPage::drawDetails(Canvas& c) {
     const auto& area = theme::kContent;
     WifiService::Connection n = wifi_.connection();
     std::vector<std::string> lines;
     if (!n.connected) {
-        lines = {statusText(), "", "`: back"};
+        lines = {statusText()};
     } else {
         lines.push_back(wifi_.ssid() + ", " + std::to_string(wifi_.rssi()) + " dBm");
         lines.push_back("Address " + n.address + "/" + std::to_string(n.prefix) + (n.fixed ? " (fixed)" : " (DHCP)"));