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>

test/test_esp32/test_main.cpp

@@ -53,6 +53,12 @@ public:
 		snprintf(s, sizeof(s), "clock %02d:%02d", hour, minute);
 		shown.push_back(s);
 	}
+	void noWifi(int hour, int minute) override
+	{
+		char s[16];
+		snprintf(s, sizeof(s), "nowifi %02d:%02d", hour, minute);
+		shown.push_back(s);
+	}
 	void logo() override { shown.push_back("logo"); }
 	void blank() override { shown.push_back("blank"); }
 
@@ -63,6 +69,7 @@ static FakePower power;
 static FakeFrames frames;
 static DisplayController *controller;
 static uint32_t now;
+static bool wifi;
 
 void setUp()
 {
@@ -71,6 +78,7 @@ void setUp()
 	delete controller;
 	controller = new DisplayController(power, frames);
 	now = 1000;
+	wifi = true;
 }
 
 void tearDown() {}
@@ -81,7 +89,7 @@ static void run(int hour, int minute, uint32_t ms = 0)
 	uint32_t end = now + ms;
 	do
 	{
-		controller->update(now, true, hour, minute);
+		controller->update(now, true, hour, minute, wifi);
 		now += 100;
 	} while ((int32_t)(end - now) >= 0);
 }
@@ -285,7 +293,12 @@ void test_recovery_never_starts_missing_clock_firmware()
 void test_every_recovery_reason_has_a_text()
 {
 	for (uint8_t r = 0; r <= (uint8_t)RecoveryReason::PowerCycle; r++)
+	{
 		TEST_ASSERT_TRUE(strlen(recoveryReasonText((RecoveryReason)r)) > 0);
+		// fits on one line of the display
+		TEST_ASSERT_TRUE(strlen(recoveryReasonShort((RecoveryReason)r)) > 0);
+		TEST_ASSERT_TRUE(strlen(recoveryReasonShort((RecoveryReason)r)) <= 14);
+	}
 	TEST_ASSERT_TRUE(strcmp(recoveryReasonText(RecoveryReason::Wifi),
 							recoveryReasonText(RecoveryReason::Crash)) != 0);
 }
@@ -318,7 +331,7 @@ void test_led_blinks_slow_with_wifi_and_fast_without()
 void test_nothing_happens_until_time_is_synced()
 {
 	power.is_on = true; // showing "Connecting..."
-	controller->update(now, false, 0, 0);
+	controller->update(now, false, 0, 0, true);
 	TEST_ASSERT_EQUAL(0, power.off_count);
 	TEST_ASSERT_EQUAL(0, (int)frames.shown.size());
 }
@@ -452,6 +465,56 @@ void test_redraws_after_power_was_switched_off_elsewhere()
 	TEST_ASSERT_EQUAL_STRING("clock 12:00", frames.last().c_str());
 }
 
+void test_no_wifi_is_shown_after_a_minute_without_wifi()
+{
+	run(12, 0);
+	wifi = false;
+	run(12, 0, NO_WIFI_SHOW_TIME - 200);
+	TEST_ASSERT_EQUAL_STRING("clock 12:00", frames.last().c_str());
+	run(12, 1, 300);
+	TEST_ASSERT_EQUAL_STRING("nowifi 12:01", frames.last().c_str());
+	TEST_ASSERT_TRUE(power.is_on);
+}
+
+void test_no_wifi_screen_keeps_the_time_running()
+{
+	wifi = false;
+	run(12, 0, NO_WIFI_SHOW_TIME + 100);
+	run(12, 1);
+	TEST_ASSERT_EQUAL_STRING("nowifi 12:01", frames.last().c_str());
+	int frames_before = (int)frames.shown.size();
+	run(12, 1, 5000);
+	TEST_ASSERT_EQUAL(frames_before, (int)frames.shown.size()); // only on change
+}
+
+void test_clock_returns_when_wifi_is_back()
+{
+	wifi = false;
+	run(12, 0, NO_WIFI_SHOW_TIME + 100);
+	wifi = true;
+	run(12, 0);
+	TEST_ASSERT_EQUAL_STRING("clock 12:00", frames.last().c_str());
+}
+
+void test_short_wifi_drop_does_not_change_the_display()
+{
+	run(12, 0);
+	wifi = false;
+	run(12, 0, 10000);
+	wifi = true;
+	run(12, 0, NO_WIFI_SHOW_TIME);
+	TEST_ASSERT_EQUAL(1, (int)frames.shown.size());
+}
+
+void test_night_without_wifi_still_powers_off()
+{
+	run(23, 30);
+	wifi = false;
+	run(23, 31, POWER_OFF_DELAY + 200);
+	TEST_ASSERT_FALSE(power.is_on);
+	TEST_ASSERT_EQUAL_STRING("blank", frames.last().c_str());
+}
+
 int main()
 {
 	UNITY_BEGIN();
@@ -501,6 +564,11 @@ int main()
 	RUN_TEST(test_clock_switch_off_never_powers_on);
 	RUN_TEST(test_clock_switch_on_again_shows_clock);
 	RUN_TEST(test_redraws_after_power_was_switched_off_elsewhere);
+	RUN_TEST(test_no_wifi_is_shown_after_a_minute_without_wifi);
+	RUN_TEST(test_no_wifi_screen_keeps_the_time_running);
+	RUN_TEST(test_clock_returns_when_wifi_is_back);
+	RUN_TEST(test_short_wifi_drop_does_not_change_the_display);
+	RUN_TEST(test_night_without_wifi_still_powers_off);
 
 	return UNITY_END();
 }