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/irc_app.cpp

@@ -299,6 +299,36 @@ void IrcApp::drawChat(Canvas& c) {
     widgets::lineEditor(c, input_, {2, area.y + area.h - inputH, area.w - 4, 0});
 }
 
+void IrcApp::help(std::vector<KeyHelp>& out) const {
+    if (page_ == Page::Settings) {
+        if (editing_) return help::textEntry(out, "keep it");
+        help::list(out, "edit, switch, or save");
+        out.push_back({"`", "leave without saving"});
+        return;
+    }
+    out.push_back({"Enter", "send the line"});
+    out.push_back({"Tab", "the next buffer"});
+    out.push_back({"Alt ; .", "scroll back, forward"});
+    out.push_back({"Fn ; .", "lines you sent before"});
+    out.push_back({"Fn , /", "move the cursor"});
+    out.push_back({"Del", "delete backwards"});
+    out.push_back({"/settings", "server, nick, passwords"});
+    out.push_back({"/join #x", "join a channel"});
+    out.push_back({"/part", "leave it"});
+    out.push_back({"/msg nick", "a private chat"});
+    out.push_back({"/me", "an action"});
+    out.push_back({"/nick", "change your nick"});
+    out.push_back({"/topic", "see or set the topic"});
+    out.push_back({"/names", "who is there"});
+    out.push_back({"/quit", "disconnect, and stay so"});
+    out.push_back({"/raw", "a line as it is"});
+    out.push_back({"`", "leave: IRC stays connected"});
+}
+
+const char* IrcApp::helpTitle() const {
+    return page_ == Page::Settings ? (editing_ ? "IRC: a setting" : "IRC settings") : nullptr;
+}
+
 void IrcApp::drawSettings(Canvas& c) {
     const auto& area = theme::kContent;
     if (editing_) {
@@ -306,8 +336,7 @@ void IrcApp::drawSettings(Canvas& c) {
         c.setTextColor(theme::kMuted);
         c.drawString(fieldLabel(fields_.selected()).c_str(), 4, area.y + 4);
         widgets::lineEditor(c, fieldEditor_, {4, area.y + 22, area.w - 8, 0});
-        c.drawString(fields_.selected() == kAutojoin ? "e.g. #roro, #private key" : "Enter: OK   `: cancel", 4,
-                     area.y + 44);
+        if (fields_.selected() == kAutojoin) c.drawString("e.g. #roro, #private key", 4, area.y + 44);
         return;
     }
     widgets::list(