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_tools_app.cpp

@@ -153,6 +153,31 @@ void WifiToolsApp::draw(Canvas& c) {
     }
 }
 
+void WifiToolsApp::help(std::vector<KeyHelp>& out) const {
+    switch (view_) {
+        case View::Menu: help::list(out); break;
+        case View::Networks:
+            help::list(out, "track its signal");
+            out.push_back({"s", "sort: signal, channel, name"});
+            out.push_back({"o", "open networks only"});
+            out.push_back({"h", "hide the hidden ones"});
+            out.push_back({"w", "strong ones only"});
+            out.push_back({"l", "log the scans to the card"});
+            break;
+        case View::Channels: break;
+        case View::Tracker: out.push_back({"m", "clicks on or off"}); break;
+    }
+}
+
+const char* WifiToolsApp::helpTitle() const {
+    switch (view_) {
+        case View::Networks: return "Networks nearby";
+        case View::Channels: return "Channel occupancy";
+        case View::Tracker: return "Signal tracker";
+        default: return nullptr;
+    }
+}
+
 void WifiToolsApp::drawNetworks(Canvas& c) {
     const auto& area = theme::kContent;
     const auto& scan = wifi_.listScan();
@@ -178,7 +203,7 @@ void WifiToolsApp::drawNetworks(Canvas& c) {
         widgets::textLines(c,
                            {wifi_.listScanDone() ? (any ? "Nothing matches the filter." : "No networks found yet.")
                                                  : "Scanning...",
-                            "", "s sort  o open  h hide-hidden  w strong  l log"},
+                            },
                            0, list);
         return;
     }
@@ -233,7 +258,7 @@ void WifiToolsApp::drawTracker(Canvas& c) {
     c.drawString(targetName_.c_str(), 4, area.y + 2);
     c.setFont(&fonts::small);
     c.setTextColor(theme::kMuted);
-    std::string sub = targetBssid_ + "  ch" + std::to_string(targetChannel_) + "  m: clicks " + (clicks_ ? "on" : "off");
+    std::string sub = targetBssid_ + "  ch" + std::to_string(targetChannel_) + "  clicks " + (clicks_ ? "on" : "off");
     c.drawString(sub.c_str(), 4, area.y + 17);
 
     c.setFont(&fonts::bold);