feat(theme): add Material 3 custom dark theme with seed #4A6741

Color.kt: New file with M3 color tokens generated from olive green
seed color #4A6741. Defines primary, secondary, tertiary, error,
surface, and container colors for the dark color scheme.

Theme.kt: Updated DarkColorScheme with all custom color tokens,
changed default to darkTheme=true, status bar now uses surface
color instead of primary for better edge-to-edge appearance.

themes.xml: Changed splash theme parent from Material.Light to
Material dark, added dark background/status/navigation bar colors
matching the Compose surface color (#1A1C18).

Closes #32

app/src/main/java/de/krisenvorrat/app/ui/theme/Color.kt

@@ -0,0 +1,63 @@
+package de.krisenvorrat.app.ui.theme
+
+import androidx.compose.ui.graphics.Color
+
+/**
+ * Material 3 color tokens generated from seed color #4A6741 (Olivgrün/Militärgrün).
+ *
+ * Generated using Material Theme Builder tonal palette algorithm.
+ * Dark theme is the primary usage.
+ */
+
+// Primary
+val md_theme_dark_primary = Color(0xFFA1D395)
+val md_theme_dark_onPrimary = Color(0xFF0B3900)
+val md_theme_dark_primaryContainer = Color(0xFF1E5110)
+val md_theme_dark_onPrimaryContainer = Color(0xFFBCEFAF)
+
+// Secondary
+val md_theme_dark_secondary = Color(0xFFBBCBB2)
+val md_theme_dark_onSecondary = Color(0xFF273422)
+val md_theme_dark_secondaryContainer = Color(0xFF3D4B37)
+val md_theme_dark_onSecondaryContainer = Color(0xFFD7E8CD)
+
+// Tertiary
+val md_theme_dark_tertiary = Color(0xFFA0D0CB)
+val md_theme_dark_onTertiary = Color(0xFF003735)
+val md_theme_dark_tertiaryContainer = Color(0xFF1E4E4C)
+val md_theme_dark_onTertiaryContainer = Color(0xFFBBECE7)
+
+// Error
+val md_theme_dark_error = Color(0xFFFFB4AB)
+val md_theme_dark_onError = Color(0xFF690005)
+val md_theme_dark_errorContainer = Color(0xFF93000A)
+val md_theme_dark_onErrorContainer = Color(0xFFFFDAD6)
+
+// Background & Surface
+val md_theme_dark_background = Color(0xFF1A1C18)
+val md_theme_dark_onBackground = Color(0xFFE2E3DC)
+val md_theme_dark_surface = Color(0xFF1A1C18)
+val md_theme_dark_onSurface = Color(0xFFE2E3DC)
+
+// Surface Variant & Outline
+val md_theme_dark_surfaceVariant = Color(0xFF424940)
+val md_theme_dark_onSurfaceVariant = Color(0xFFC2C9BD)
+val md_theme_dark_outline = Color(0xFF8C9388)
+val md_theme_dark_outlineVariant = Color(0xFF424940)
+
+// Inverse
+val md_theme_dark_inverseSurface = Color(0xFFE2E3DC)
+val md_theme_dark_inverseOnSurface = Color(0xFF2F312C)
+val md_theme_dark_inversePrimary = Color(0xFF336B25)
+
+// Scrim
+val md_theme_dark_scrim = Color(0xFF000000)
+
+// Surface containers
+val md_theme_dark_surfaceDim = Color(0xFF1A1C18)
+val md_theme_dark_surfaceBright = Color(0xFF404F3D)
+val md_theme_dark_surfaceContainerLowest = Color(0xFF0F120D)
+val md_theme_dark_surfaceContainerLow = Color(0xFF222520)
+val md_theme_dark_surfaceContainer = Color(0xFF262924)
+val md_theme_dark_surfaceContainerHigh = Color(0xFF31342E)
+val md_theme_dark_surfaceContainerHighest = Color(0xFF3C3F39)

app/src/main/java/de/krisenvorrat/app/ui/theme/Theme.kt

@@ -10,12 +10,49 @@ import androidx.compose.ui.graphics.toArgb
 import androidx.compose.ui.platform.LocalView
 import androidx.core.view.WindowCompat
 
-private val DarkColorScheme = darkColorScheme()
+private val DarkColorScheme = darkColorScheme(
+    primary = md_theme_dark_primary,
+    onPrimary = md_theme_dark_onPrimary,
+    primaryContainer = md_theme_dark_primaryContainer,
+    onPrimaryContainer = md_theme_dark_onPrimaryContainer,
+    secondary = md_theme_dark_secondary,
+    onSecondary = md_theme_dark_onSecondary,
+    secondaryContainer = md_theme_dark_secondaryContainer,
+    onSecondaryContainer = md_theme_dark_onSecondaryContainer,
+    tertiary = md_theme_dark_tertiary,
+    onTertiary = md_theme_dark_onTertiary,
+    tertiaryContainer = md_theme_dark_tertiaryContainer,
+    onTertiaryContainer = md_theme_dark_onTertiaryContainer,
+    error = md_theme_dark_error,
+    onError = md_theme_dark_onError,
+    errorContainer = md_theme_dark_errorContainer,
+    onErrorContainer = md_theme_dark_onErrorContainer,
+    background = md_theme_dark_background,
+    onBackground = md_theme_dark_onBackground,
+    surface = md_theme_dark_surface,
+    onSurface = md_theme_dark_onSurface,
+    surfaceVariant = md_theme_dark_surfaceVariant,
+    onSurfaceVariant = md_theme_dark_onSurfaceVariant,
+    outline = md_theme_dark_outline,
+    outlineVariant = md_theme_dark_outlineVariant,
+    inverseSurface = md_theme_dark_inverseSurface,
+    inverseOnSurface = md_theme_dark_inverseOnSurface,
+    inversePrimary = md_theme_dark_inversePrimary,
+    scrim = md_theme_dark_scrim,
+    surfaceDim = md_theme_dark_surfaceDim,
+    surfaceBright = md_theme_dark_surfaceBright,
+    surfaceContainerLowest = md_theme_dark_surfaceContainerLowest,
+    surfaceContainerLow = md_theme_dark_surfaceContainerLow,
+    surfaceContainer = md_theme_dark_surfaceContainer,
+    surfaceContainerHigh = md_theme_dark_surfaceContainerHigh,
+    surfaceContainerHighest = md_theme_dark_surfaceContainerHighest,
+)
+
 private val LightColorScheme = lightColorScheme()
 
 @Composable
 fun KrisenvorratTheme(
-    darkTheme: Boolean = false,
+    darkTheme: Boolean = true,
     content: @Composable () -> Unit
 ) {
     val colorScheme = if (darkTheme) DarkColorScheme else LightColorScheme
@@ -23,7 +60,7 @@ fun KrisenvorratTheme(
     if (!view.isInEditMode) {
         SideEffect {
             val window = (view.context as Activity).window
-            window.statusBarColor = colorScheme.primary.toArgb()
+            window.statusBarColor = colorScheme.surface.toArgb()
             WindowCompat.getInsetsController(window, view).isAppearanceLightStatusBars = !darkTheme
         }
     }

app/src/main/res/values/themes.xml

@@ -1,4 +1,10 @@
 <?xml version="1.0" encoding="utf-8"?>
 <resources>
-    <style name="Theme.Krisenvorrat" parent="android:Theme.Material.Light.NoActionBar" />
+    <color name="splash_background">#1A1C18</color>
+
+    <style name="Theme.Krisenvorrat" parent="android:Theme.Material.NoActionBar">
+        <item name="android:windowBackground">@color/splash_background</item>
+        <item name="android:statusBarColor">@color/splash_background</item>
+        <item name="android:navigationBarColor">@color/splash_background</item>
+    </style>
 </resources>