Show status messages on the display

- Clock firmware: 'Connecting to WiFi...' and 'Getting the time...' at
  boot, 'Crashed!' in the OTA-only modes, and 'No WiFi' with the time
  when WiFi is down for over a minute (new DisplayController screen)
- Recovery app: shows its reason, the setup WiFi name, or its IP address,
  then powers the display off (flipdots keep the image)
- StatusScreen and drawTextLines shared by both apps
- Driver: ESP begin() no longer draws 'ESP Connected'
- Tests: No WiFi screen, short reason texts (70 total)

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/esp32/display/status_screen.h

@@ -0,0 +1,21 @@
+#pragma once
+
+#include "BROSE9323.h"
+#include "nano_link/nano_link.h"
+
+// Short messages for situations outside the normal clock: booting, crashes, recovery app.
+// Used by both the clock firmware and the recovery app.
+class StatusScreen
+{
+public:
+	StatusScreen(BROSE9323 &display, NanoLink &nano);
+
+	// Power the display on, show up to two lines (TEXT_LINE_CHARS each). Unless keep_on,
+	// power off again once the dots have flipped: flipdots keep their image without power.
+	void show(const char *line1, const char *line2, bool keep_on = false);
+
+private:
+	BROSE9323 &_display;
+	NanoLink &_nano;
+	bool _started = false;
+};