feat(theme): add the Orchid app theme

The phone keyboard's own palette, ported rather than re-invented: page
violet-black, letter pink as the soft accent, alternate-symbol violet as the
secondary, activated-key violet for filled chips, the off-peak gauge blue as
tertiary and the peak pink as the error colour.

- BrandPalettes.Orchid: darkBrand seed set carrying the keyboard values.
- AppThemes.Orchid: DARK_ONLY, registered last in the picker.
- StoreScreenshotTest: per-theme gallery render, matching the existing
  one-render-per-theme convention.

app/src/main/kotlin/com/hermesandroid/relay/ui/theme/BrandPalette.kt

@@ -446,6 +446,31 @@ object BrandPalettes {
         ink = Color(0xFFFAE6EE),
         paper = Color(0xFFFFD4E1),
     )
+
+    /**
+     * Orchid — the phone keyboard's palette, ported (2026-09-27).
+     *
+     * Sampled from the keyboard's own theme rather than re-invented, so the app
+     * wears the same look as the keyboard it is typed on: the keyboard's page
+     * colour becomes the background, its letter pink the soft accent, the
+     * alternate-symbol violet the secondary, and the activated-key violet the
+     * filled-chip accent. The tertiary keeps the keyboard's off-peak gauge blue
+     * and `danger` its peak pink, so the two state colours the keyboard already
+     * speaks stay meaningful in the app.
+     */
+    val Orchid = darkBrand(
+        background = Color(0xFF100A1C),   // keyboard `colorKeyboard`
+        panel = Color(0xFF1D1330),        // one step off the page for elevated panels
+        relay = Color(0xFFFF8AD8),        // keyboard `colorLabel` (pink)
+        purple = Color(0xFFC67DFF),       // keyboard `colorSubLabel` (violet)
+        electric = Color(0xFFA855F7),     // keyboard `colorKeyActivated`
+        cyan = Color(0xFF00E5FF),         // keyboard off-peak gauge blue
+        ink = Color(0xFFF9F4FF),
+        paper = Color(0xFFEFE7FF),
+        muted = Color(0xFFB0A2CC),
+        dim = Color(0xFF7A6E96),
+        danger = Color(0xFFFF2D95),       // keyboard peak pink
+    )
 }
 
 /** Whether a theme honors a separate light/dark mode toggle, or is a fixed look. */
@@ -568,6 +593,17 @@ object AppThemes {
         swatch = listOf(Color(0xFF1A0F15), Color(0xFFE86A9C), Color(0xFFFFD4E1)),
     )
 
+    /** Orchid — the phone keyboard's own theme, carried into the app. */
+    val Orchid = AppTheme(
+        id = "orchid",
+        label = "Orchid",
+        description = "The phone keyboard's palette — pink and violet on deep violet-black",
+        mode = ThemeMode.DARK_ONLY,
+        darkPalette = BrandPalettes.Orchid,
+        lightPalette = BrandPalettes.Orchid,
+        swatch = listOf(Color(0xFF100A1C), Color(0xFFA855F7), Color(0xFFFF8AD8)),
+    )
+
     /** All themes in picker order: brand first, then the Nous baselines. */
     val ALL: List<AppTheme> = listOf(
         HermesRelay,
@@ -578,6 +614,7 @@ object AppThemes {
         Mono,
         Cyberpunk,
         Rose,
+        Orchid,
     )
 
     private val byId = ALL.associateBy { it.id }

app/src/test/kotlin/com/hermesandroid/relay/screenshots/StoreScreenshotTest.kt

@@ -331,6 +331,7 @@ class StoreScreenshotTest {
     @Test fun g_mono() = capture("gallery_mono", "mono") { ChatScene() }
     @Test fun g_cyberpunk() = capture("gallery_cyberpunk", "cyberpunk") { ChatScene() }
     @Test fun g_rose() = capture("gallery_rose", "rose") { ChatScene() }
+    @Test fun g_orchid() = capture("gallery_orchid", "orchid") { ChatScene() }
 }
 
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