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/config.h

@@ -36,6 +36,11 @@ const uint32_t NANO_BOOT_TIMEOUT = 3000;
 
 // After a frame is cleared, wait this long before cutting the power, so the dots can flip
 const uint32_t CLEAR_BEFORE_OFF_TIME = 1000;
+// Status messages (boot, crash, recovery): time for the Nano to flip all dots before the
+// power is cut again. The message stays visible without power.
+const uint32_t STATUS_FLIP_TIME = 2000;
+// WiFi down this long while the clock runs: show "No WiFi" with the time instead
+const uint32_t NO_WIFI_SHOW_TIME = 60000;
 // Power off this long after the display is no longer needed (night, standby, logo)
 const uint32_t POWER_OFF_DELAY = 30000;