Portrait 360x480 table with regular-sized flippers

Rotate the playfield to portrait like a real pinball machine:
- canvas 480x360 landscape -> 360x480 portrait; playfield 308px wide,
  ~390px tall, with HUD, title/game-over screens and HUD re-laid out
  for the narrow format (score/best top row, balls/stars/fever below)
- flippers reduced to a regular ~quarter-width size (82px) pivoting at
  the lower corners, tips meeting over a wide centre drain
- table elements re-placed for the taller field: 3 star lanes up top,
  candy bumpers mid-field, slingshots and floor-level outlane guard
  posts at the bottom; data-checked with the autoplay bot (~350 bumper
  hits / 30k frames, centre+side drains, no stuck balls)
- probes & autoplay policy updated for the portrait geometry; all 13
  pixel-probes pass

README.md

@@ -6,8 +6,8 @@ audio asset files**: every sprite, texture, particle, chiptune and sound
 effect is generated by code at runtime.
 
 Not web-based: it opens its own native window and renders on a low-res
-`480×360` virtual canvas, upscaled with crisp nearest-neighbour scaling for an
-authentic retro look.
+**portrait** `360×480` virtual canvas — like a proper pinball machine —
+upscaled with crisp nearest-neighbour scaling for an authentic retro look.
 
 ![demo](shots/3_play.png)