Landscape orientation, redesigned web UI, rotation on/off + minutes, weather by city name

- Panel is mounted sideways: render landscape (600x400), rotate to the
  panel's native portrait orientation right before writing to hardware.
- Web UI: card-based layout, dark mode, active nav highlighting, save
  confirmation toasts, error banners.
- Rotation: separate enabled/disabled toggle (off pins to the first screen
  in the list) and the interval is now in minutes instead of raw seconds.
  Migrates existing config.json from the old interval_seconds field.
- Weather: type a city name instead of hunting down coordinates, resolved
  via Open-Meteo's free geocoding API. Manual lat/long still available as
  a fallback.

display/epd4in0e_driver.py

@@ -13,7 +13,11 @@ from display import Display
 
 logger = logging.getLogger(__name__)
 
-RESOLUTION = (400, 600)
+# The panel is physically native portrait (400x600), but mounted sideways --
+# screens render in this landscape resolution, and show() rotates the frame
+# to match the panel's native orientation right before sending it over.
+RESOLUTION = (600, 400)
+PANEL_NATIVE_RESOLUTION = (400, 600)
 
 
 class EPD4in0eDisplay(Display):
@@ -46,7 +50,14 @@ class EPD4in0eDisplay(Display):
         # full flash, there's no way around it on this panel.
         self._epd.Clear()
 
-        self._epd.display(self._epd.getbuffer(image.convert("RGB")))
+        # Rotate landscape -> the panel's native portrait orientation. If this
+        # comes out upside-down for how it's physically mounted, flip the
+        # sign here (rotate(-90) instead of rotate(90)).
+        rotated = image.convert("RGB").rotate(90, expand=True)
+        if rotated.size != PANEL_NATIVE_RESOLUTION:
+            raise ValueError(f"Rotated image {rotated.size} doesn't match panel {PANEL_NATIVE_RESOLUTION}")
+
+        self._epd.display(self._epd.getbuffer(rotated))
 
     def sleep(self) -> None:
         if self._epd is not None: