perf(icons): share FontFamily + TextMeasurer across Material Symbol icons

Material Symbol icons were allocating a fresh Font wrapper on every
composition (Font(resource = ...) returns a new instance each call),
which invalidated the remember(font) cache in rememberMaterialSymbolsFontFamily
and forced a fresh TextMeasurer per call site. Tint was also baked into
the TextStyle passed to measure(), so any tint change (selected /
unselected reaction icons, hover states) produced a cache miss.

Hoist the FontFamily + TextMeasurer to CompositionLocals provided once
at the root (AmethystTheme on Android, MaterialTheme wrapper on desktop)
via ProvideMaterialSymbols. Every icon in the subtree now reuses:

- One FontFamily (Skia typeface cache hit for every subsequent glyph)
- One TextMeasurer with a 64-entry LRU, shared across all call sites
  so its measurement cache is hit across 300+ MaterialSymbols usages
- Tint applied via drawText(layout, color = tint) instead of TextStyle,
  so the measured TextLayoutResult is reused across tint variations

Icon(symbol = ...) now delegates to Material3's Icon(painter = ...),
restoring proper sizing/semantics without the custom Box+drawBehind
workaround. autoMirror handled inside the painter's onDraw. The
previously-unused MaterialSymbolPainter is now the single render path.

The weight parameter is dropped from the Icon/Painter APIs since the
app uses a single weight globally (MaterialSymbolsDefaults.WEIGHT).

A local fallback path keeps @Preview composables that don't wrap in
the theme renderable (per-composition allocation, same cost as before).

https://claude.ai/code/session_01V9esGUFH72ujCQNWCAnjKN

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/theme/Theme.kt

@@ -61,6 +61,7 @@ import com.halilibo.richtext.ui.resolveDefaults
 import com.patrykandpatrick.vico.compose.common.VicoTheme
 import com.patrykandpatrick.vico.compose.common.VicoTheme.CandlestickCartesianLayerColors
 import com.vitorpamplona.amethyst.Amethyst
+import com.vitorpamplona.amethyst.commons.icons.symbols.ProvideMaterialSymbols
 import com.vitorpamplona.amethyst.model.ThemeType
 
 private val DarkColorPalette =
@@ -591,7 +592,7 @@ fun AmethystTheme(
         colorScheme = colors,
         typography = Typography,
         shapes = Shapes,
-        content = content,
+        content = { ProvideMaterialSymbols(content) },
     )
 
     val view = LocalView.current