feat: collapsible Flex/amp/tuner cards, matched meter sizes, faster + distinct-icon TGXL

Addresses three points of feedback on the Tuner Genius work:

- Meter sizes: the amplifier meters were rendered `compact` (smaller than the
  FlexRadio meters). Dropped compact so the amp, tuner and Flex meters are all
  the same size.
- Collapsible cards: the FlexRadio panel Card, AmpCard and TunerCard now fold
  from a chevron in the header, state persisted per card (opslog.cardOpen.*).
  The amplifier cards share the "amplifier" collapse key across their SPE/ACOM/
  PGXL variants so folding sticks regardless of the shown model.
- TGXL responsiveness: the tuner's device poll dropped 1500ms→400ms and the
  three UI pollers 1500ms→500ms, so the SWR/power meters track TX without the
  2–3s lag behind the amplifier the user saw.
- Icon: the Tuner Genius top-bar toggle used Zap, same as the CW keyer — changed
  the tuner's icon (top bar + widget + card) to Gauge so the two are distinct.

internal/tunergenius/tunergenius.go

@@ -29,9 +29,12 @@ const (
 	// UDP discovery broadcast use 9010).
 	DefaultPort = 9010
 
-	dialTimeout    = 5 * time.Second
-	ioTimeout      = 3 * time.Second
-	pollEvery      = 1500 * time.Millisecond
+	dialTimeout = 5 * time.Second
+	ioTimeout   = 3 * time.Second
+	// Poll fast so the meters track TX like the amplifier does (the amp's numbers
+	// ride the real-time Flex UDP stream; the tuner is a synchronous TCP poll, so
+	// a slow interval made its SWR/power lag noticeably behind).
+	pollEvery      = 400 * time.Millisecond
 	reconnectDelay = 2 * time.Second
 )