G1 step 4: the Gemini App (rendering, links, history, address line)

Gemtext as Q75 has it: headings bold (# in the accent colour), lists
with a middle dot, quotes muted, links as » labels, preformatted lines
unwrapped and scrolled sideways together; other text/* as is. Pages are
wrapped once for each line's first row (4 bytes a line) and only the
lines on screen are wrapped again to draw. Tab and Shift+Tab move
between links, Enter follows (relative links resolved), Back or Delete
go back to where the page was scrolled, g opens the address line.
Non-Gemini links say so in the URL bar; a changed certificate opens a
dialog; errors and refusals get a page with a "Try again" link; a page
only partly in memory says why at its end.

A status message timed with millis() after the loop's clock read was
cleared before it was drawn (unsigned wrap): now a signed comparison,
as for the toasts in M0.

Verified on the device: start page, Project Gemini, its relative news/
link, Back with the scroll restored, and the YouTube link refused.

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

src/main.cpp

@@ -8,6 +8,7 @@
 
 #include "app_manager.h"
 #include "apps/demo_app.h"
+#include "apps/gemini_app.h"
 #include "apps/gnss_app.h"
 #include "apps/irc_app.h"
 #include "apps/launcher_app.h"
@@ -174,6 +175,7 @@ void setup() {
     apps->registerApp({"irc", "IRC", false, new IrcApp(*irc, *clockService, bus)});
     apps->registerApp({"wifi-tools", "Wi-Fi Tools", false, new WifiToolsApp(*wifi, *storageService, *clockService)});
     apps->registerApp({"gnss", "GNSS", false, new GnssApp(*gnssService, settings)});
+    apps->registerApp({"gemini", "Gemini", false, new GeminiApp(*geminiService)});
     apps->registerApp({"settings", "Settings", false,
                        new SettingsApp({settings, bus, *apps, *battery, *storageService, *clockService, *wifi, *savedNetworks, *update})});
     apps->registerApp({"demo", "Widget demo", true, new DemoApp(bus)});