next iteration on display, still some artifacting issues, and ux with buttons states and updating

sim/sim_main.c

@@ -233,6 +233,24 @@ static void apply_mock_data(void)
     sim_data.lights[0].brightness = 178;          /* 70% */
     sim_data.lights[4].state = HA_LIGHT_UNAVAILABLE;
 
+    /*
+     * Synthetic trend history: an "hour-old" anchor per channel so the
+     * arrows render in the mock. Unsigned tick arithmetic makes now-55min
+     * safe even seconds after boot. Snapshot mode gets no history and shows
+     * no arrows -- which is exactly what a freshly booted device does.
+     */
+    const uint32_t now = lv_tick_get();
+    const uint32_t hour_ago = now - 55u * 60u * 1000u;
+    ha_trend_feed(HA_TREND_CH_INDOOR, 77.1f, hour_ago);      /* -> rising  */
+    ha_trend_feed(HA_TREND_CH_INDOOR, 78.1f, now);
+    ha_trend_feed(HA_TREND_CH_OUTDOOR, 74.6f, hour_ago);     /* -> falling */
+    ha_trend_feed(HA_TREND_CH_OUTDOOR, 73.0f, now);
+    ha_trend_feed(HA_TREND_CH_PRESSURE, 29.95f, hour_ago);   /* -> falling */
+    ha_trend_feed(HA_TREND_CH_PRESSURE, 29.89f, now);
+    sim_data.trend_indoor   = ha_trend_compute(HA_TREND_CH_INDOOR, 0.5f, now);
+    sim_data.trend_outdoor  = ha_trend_compute(HA_TREND_CH_OUTDOOR, 0.5f, now);
+    sim_data.trend_pressure = ha_trend_compute(HA_TREND_CH_PRESSURE, 0.02f, now);
+
     static const char *const days[HA_FORECAST_DAYS] = { "Tue", "Wed", "Thu", "Fri", "Sat" };
     static const char *const cond[HA_FORECAST_DAYS] = {
         "partlycloudy", "sunny", "sunny", "clear-night", "rainy"