Smooth graphs, sun path card, skeleton page switches and editor drag & drop

Firmware 0.2.15: trend graphs use a Catmull-Rom curve with a soft fill
drawn by the card's draw event; sun.sun gets a wide sun-path card with
horizon, arc and the sun at its current position; page switches show
the new page's card frames immediately and fill them from a one-shot
timer; the navigation is one full-width bar without a divider; the CYD
adopts the Guition light palette in styles and overlays.

App 0.2.13: pointer-based drag & drop (mouse and touch) to reorder tiles
in the mockup and to drop entities from the list, sticky save bar, a new
header with explained actions and a three-step guide, clearer firmware
dialog. New sun, weather and clock tiles start wide in their best view.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

tests/test_extended.py

@@ -62,6 +62,7 @@ class SpecialTiles(unittest.TestCase):
   layout=validate_layout({'title':'T','tiles':[{'entity':'screen.clock','options':{'display':'analog','size':'wide'}},{'entity':'sun.sun'},{'entity':'timer.egg'},{'entity':'person.max'},
    {'entity':'weather.home','options':{'display':'forecast'}},{'entity':'sensor.t','options':{'display':'graph','size':'wide'}}]})
   self.assertEqual(layout['tiles'][4]['options'],{'display':'forecast','size':'wide'},'forecast forces a wide card')
+  self.assertEqual(validate_layout({'title':'T','tiles':[{'entity':'sun.sun','options':{'display':'sunpath'}}]})['tiles'][0]['options'],{'display':'sunpath','size':'wide'})
   self.assertEqual(layout['tiles'][0]['options']['display'],'analog')
   for tile in [{'entity':'screen.other'},{'entity':'light.a','options':{'size':'double'}},{'entity':'light.a','options':{'display':'graph'}},
                {'entity':'sensor.a','options':{'display':'forecast'}},{'entity':'screen.clock','options':{'display':'watch'}}]: