fix(chat): tint composer send/stop/mic button with theme primary (#1410)

app/src/main/java/com/m57/hermescontrol/theme/Color.kt

@@ -91,3 +91,6 @@ fun parseProjectColor(raw: String?): Color? {
     if (h !in 0f..360f || s !in 0f..1f || l !in 0f..1f) return null
     return Color.hsl(h % 360f, s, l)
 }
+
+/** Pure white glyph for filled accent controls (composer action button) when it is legible on the preset primary. */
+val GlyphWhite = Color(0xFFFFFFFF)

app/src/main/java/com/m57/hermescontrol/ui/chat/components/ComposerPalette.kt

@@ -6,6 +6,8 @@ import androidx.compose.runtime.Composable
 import androidx.compose.runtime.ReadOnlyComposable
 import androidx.compose.ui.graphics.Color
 import androidx.compose.ui.graphics.compositeOver
+import androidx.compose.ui.graphics.luminance
+import com.m57.hermescontrol.theme.GlyphWhite
 
 /**
  * Resolved colors for the chat composer card and its controls.
@@ -15,7 +17,8 @@ import androidx.compose.ui.graphics.compositeOver
  * (Nord's High and Highest are the same color), which made the flat controls
  * vanish into the card. A fixed onSurface tint keeps them visible in every
  * preset and under dynamic color. Text and icon contrast is gated per preset
- * in ComposerPaletteTest.
+ * in ComposerPaletteTest. The send / stop / mic action button is the one
+ * themed control: it takes the preset's primary so it follows the theme tint.
  */
 internal data class ComposerPalette(
     val card: Color,
@@ -30,10 +33,30 @@ internal data class ComposerPalette(
 )
 
 private const val CONTROL_TINT_ALPHA = 0.12f
+private const val ACTION_MIN_CONTRAST = 3f
+
+private fun contrastRatio(
+    a: Color,
+    b: Color,
+): Float {
+    val l1 = a.luminance()
+    val l2 = b.luminance()
+    return (maxOf(l1, l2) + 0.05f) / (minOf(l1, l2) + 0.05f)
+}
 
 internal fun composerPalette(scheme: ColorScheme): ComposerPalette {
     val card = scheme.surfaceContainer
     val tint = scheme.onSurface.copy(alpha = CONTROL_TINT_ALPHA)
+    // Pastel primaries (Nord light) vanish on the card; keep the neutral fill there.
+    val tinted = contrastRatio(scheme.primary, card) >= ACTION_MIN_CONTRAST
+    val action = if (tinted) scheme.primary else scheme.onSurface
+    // White glyph wherever it clears 3:1 on the primary; pastel primaries keep their own dark onPrimary.
+    val onAction =
+        when {
+            !tinted -> scheme.surface
+            contrastRatio(GlyphWhite, scheme.primary) >= ACTION_MIN_CONTRAST -> GlyphWhite
+            else -> scheme.onPrimary
+        }
     return ComposerPalette(
         card = card,
         cardBorder = tint.compositeOver(scheme.background),
@@ -42,8 +65,8 @@ internal fun composerPalette(scheme: ColorScheme): ComposerPalette {
         control = tint.compositeOver(card),
         onControl = scheme.onSurface,
         onControlVariant = scheme.onSurfaceVariant,
-        action = scheme.onSurface,
-        onAction = scheme.surface,
+        action = action,
+        onAction = onAction,
     )
 }