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/logic/display_controller.h

@@ -19,6 +19,8 @@ class Frames
 {
 public:
 	virtual void clock(int hour, int minute) = 0;
+	// Shown instead of the clock while WiFi is down (the time keeps running without it)
+	virtual void noWifi(int hour, int minute) = 0;
 	virtual void logo() = 0;
 	virtual void blank() = 0;
 };
@@ -40,13 +42,15 @@ public:
 	bool powerEnabled() const;
 
 	// Call often (every loop). time_valid is false until the time is synced over NTP.
-	void update(uint32_t now, bool time_valid, int hour, int minute);
+	// While WiFi is down for NO_WIFI_SHOW_TIME, "No WiFi" is shown instead of the clock.
+	void update(uint32_t now, bool time_valid, int hour, int minute, bool wifi_connected);
 
 private:
 	enum class Screen
 	{
 		Unknown, // nothing sent since the last power on
 		Clock,
+		NoWifi,
 		Logo,
 		Blank,
 	};
@@ -62,7 +66,10 @@ private:
 	int _shown_hour = -1;
 	int _shown_minute = -1;
 
-	void _showClock(int hour, int minute);
+	bool _wifi_lost = false;
+	uint32_t _wifi_lost_since = 0;
+
+	void _showClock(int hour, int minute, bool no_wifi);
 	void _showLogo();
 	void _showBlank();
 };