feat: orb uses rememberTiltState(), update CLAUDE.md with i18n + migration status

KaizenOrb now uses centralized rememberTiltState() (GAME_ROTATION_VECTOR,
lifecycle-aware, battery-saver-aware) instead of inline sensor code.
Breath animation uses Durations tokens from motion system.

CLAUDE.md: updated design system section with GlassSurface correction
(no backdrop-filter on Android), migration status (all components done),
i18n section documenting the de/en string resource architecture.

CLAUDE.md

@@ -48,7 +48,7 @@ ui/
   theme/        Color (P3), Theme (multi-theme), Type, Oklab, Dither
   theme/themes/ AccentScheme, AmberTheme, BlauTheme, MonoTheme, AuroraTheme, ThemeRegistry
   shape/        SquircleShape (superellipse), KaizenShapes (token system)
-  effect/       GlassSurface (RenderEffect blur), Shadow (multi-layer stack)
+  effect/       GlassSurface (frosted glass), Shadow (multi-layer stack)
   motion/       Motion (easing curves, spring specs, duration tokens)
   sensor/       TiltState (gyro/accel parallax, lifecycle-aware)
 ```
@@ -69,14 +69,26 @@ Full spec: `DESIGN.md`. Branch: `feature/design-system-v2`.
 
 1. **P3 color pipeline** — all tokens in DisplayP3 color space (`Color.kt`). `window.colorMode = COLOR_MODE_HDR` (API 34+) / `COLOR_MODE_WIDE_COLOR_GAMUT` (API 26+) in `MainActivity`. No `Color(0xFF…)` for brand colors outside `Color.kt`.
 2. **Squircle shapes** — iOS-style superellipse with G2 continuity (`ui/shape/Squircle.kt`). Token system `KaizenShapes.{xs,sm,md,lg,xl,pill,circle}`. Replaces all `RoundedCornerShape`.
-3. **GlassSurface** — real `Modifier.blur()` (RenderEffect on API 31+), tint + inner highlight + border. API 26–30 fallback: higher tint alpha. Opacity tiers per component in `GlassTiers`.
+3. **GlassSurface** — frosted-glass composable (gradient tint + specular border + inner highlight + multi-layer shadow). Android has no backdrop-filter; glass effect works via semi-transparent tint over the blob layer. Opacity tiers per component in `GlassTiers`.
 4. **Multi-layer shadows** — `ShadowStack` with 2–4 overlapping layers (`KaizenShadows.level0..4`). Dark mode multiplies alphas ×1.8. Replaces all `Modifier.shadow()`.
 5. **4-theme system** — Amber/Blau/Mono/Aurora. Each theme = `KaizenAccentScheme` (primary + 4 blob colors). Neutrals are theme-independent. `LocalKaizenAccent` CompositionLocal. Server sync planned via `GET /api/v1/me` → `uiTheme`.
 6. **Sensor-reactive motion** — `rememberTiltState()` provides smoothed tilt `Offset(-1..1)`. Uses `TYPE_GAME_ROTATION_VECTOR` (fused, no drift). Auto-disables on battery saver, reduced motion, background, extreme tilt.
 
 **Motion tokens** (`ui/motion/Motion.kt`): `EaseSpring` (overshoot), `EaseSmooth` (expo-out), `EaseEmphasized` (M3), `SpringSnappy/Default/Gentle`. All durations centralised in `Durations` object.
 
-**What's NOT yet migrated to the design system:** The existing UI components (ChatScreen, Sidebar, ChatInput, etc.) still use the old inline glass styling with manual `Brush` + `border`. Migration to `GlassSurface` + `KaizenShapes` + `kaizenShadow` is the next step.
+**Migration status:** All UI components migrated to the design system. Sidebar, ChatInput, ChatScreen, LoginScreen, ModelSheet, SettingsCard, SettingsScreen use `GlassSurface` + `KaizenShapes` + `kaizenShadow`. Only Markdown code-block shapes remain as `RoundedCornerShape` (intentionally rectangular for code).
+
+**KaizenOrb** (`chat/Background.kt`) uses `rememberTiltState()` from `ui/sensor/` instead of inline sensor code. Breath animation uses `Durations.ORB_BREATH` / `ORB_BREATH_STREAMING` from `ui/motion/`.
+
+### Internationalization (i18n)
+
+- **de** (default), **en** — same as web (`messages/de.json`, `messages/en.json`).
+- Strings: `res/values/strings.xml` (de) + `res/values-en/strings.xml` (en).
+- All UI strings use `stringResource(R.string.xxx)` in `@Composable` functions, or `context.getString(R.string.xxx)` in non-composable contexts (error handlers, coroutines).
+- Date/time: `DateTimeFormatter` with `Locale.getDefault()`.
+- Greeting: time-of-day-based (Morgen/Tag/Abend → Morning/Afternoon/Evening), boundaries 5/12/18.
+- ChatModels: `Suggestion.labelRes`/`promptRes` and `ChatMode.labelRes` are resource IDs (Int), not hardcoded strings.
+- `ModePillsRow`: `selected` state is `Int` (resource ID), not `String`.
 
 ### Offline-first cache layer (Room) — added 2026-06-21
 

app/src/main/java/dev/kaizen/app/chat/Background.kt

@@ -1,23 +1,14 @@
 package dev.kaizen.app.chat
 
-import android.content.Context
-import android.hardware.Sensor
-import android.hardware.SensorEvent
-import android.hardware.SensorEventListener
-import android.hardware.SensorManager
 import androidx.compose.animation.core.FastOutSlowInEasing
 import androidx.compose.animation.core.LinearEasing
 import androidx.compose.animation.core.RepeatMode
-import androidx.compose.animation.core.Spring
 import androidx.compose.animation.core.animateFloat
-import androidx.compose.animation.core.animateFloatAsState
 import androidx.compose.animation.core.infiniteRepeatable
 import androidx.compose.animation.core.rememberInfiniteTransition
-import androidx.compose.animation.core.spring
 import androidx.compose.animation.core.tween
 import androidx.compose.foundation.Canvas
 import androidx.compose.foundation.background
-import androidx.compose.foundation.border
 import androidx.compose.foundation.isSystemInDarkTheme
 import androidx.compose.foundation.layout.Box
 import androidx.compose.foundation.layout.BoxScope
@@ -27,11 +18,7 @@ import androidx.compose.foundation.layout.size
 import androidx.compose.foundation.shape.CircleShape
 import androidx.compose.material3.MaterialTheme
 import androidx.compose.runtime.Composable
-import androidx.compose.runtime.DisposableEffect
 import androidx.compose.runtime.getValue
-import androidx.compose.runtime.mutableStateOf
-import androidx.compose.runtime.remember
-import androidx.compose.runtime.setValue
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.draw.BlurredEdgeTreatment
@@ -44,9 +31,10 @@ import androidx.compose.ui.graphics.Brush
 import androidx.compose.ui.graphics.Color
 import androidx.compose.ui.graphics.drawscope.Stroke
 import androidx.compose.ui.input.pointer.pointerInput
-import androidx.compose.ui.platform.LocalContext
 import androidx.compose.ui.unit.Dp
 import androidx.compose.ui.unit.dp
+import dev.kaizen.app.ui.motion.Durations
+import dev.kaizen.app.ui.sensor.rememberTiltState
 import dev.kaizen.app.ui.theme.Amber
 import dev.kaizen.app.ui.theme.AmberDeep
 import dev.kaizen.app.ui.theme.BlobAmber
@@ -132,58 +120,17 @@ fun KaizenOrb(
         initialValue = 1f,
         targetValue = if (streaming || recording) 1.05f else 1.025f,
         animationSpec = infiniteRepeatable(
-            tween(if (streaming || recording) 2400 else 7000, easing = FastOutSlowInEasing),
+            tween(if (streaming || recording) Durations.ORB_BREATH_STREAMING else Durations.ORB_BREATH, easing = FastOutSlowInEasing),
             RepeatMode.Reverse,
         ),
         label = "breath",
     )
 
-    // Dynamic scale expansion based on real-time audio amplitude (Call Mode / TTS speech reactivity)
     val reactiveScale = amplitude?.let { 1f + it * 0.12f } ?: 1f
 
-    // --- Gyroscope / Accel-based Holographic Parallax Offset ---
+    val tilt by rememberTiltState()
-    val context = LocalContext.current
+    val tiltX = tilt.x
-    var rawTiltX by remember { mutableStateOf(0f) }
+    val tiltY = tilt.y
-    var rawTiltY by remember { mutableStateOf(0f) }
-
-    DisposableEffect(Unit) {
-        val sensorManager = context.getSystemService(Context.SENSOR_SERVICE) as? SensorManager
-        val gravitySensor = sensorManager?.getDefaultSensor(Sensor.TYPE_GRAVITY)
-            ?: sensorManager?.getDefaultSensor(Sensor.TYPE_ACCELEROMETER)
-
-        val listener = object : SensorEventListener {
-            override fun onSensorChanged(event: SensorEvent?) {
-                if (event == null) return
-                // event.values[0] is X (left/right tilt), event.values[1] is Y (forward/backward tilt)
-                // Normalize gravity acceleration to unit scale [-1.0, 1.0]
-                val x = event.values[0] / 9.81f
-                val y = event.values[1] / 9.81f
-                rawTiltX = x.coerceIn(-1f, 1f)
-                rawTiltY = y.coerceIn(-1f, 1f)
-            }
-            override fun onAccuracyChanged(sensor: Sensor?, accuracy: Int) {}
-        }
-
-        if (sensorManager != null && gravitySensor != null) {
-            sensorManager.registerListener(listener, gravitySensor, SensorManager.SENSOR_DELAY_UI)
-        }
-
-        onDispose {
-            sensorManager?.unregisterListener(listener)
-        }
-    }
-
-    // Smooth raw tilt values using native springs for fluid, liquid responsiveness
-    val tiltX by animateFloatAsState(
-        targetValue = rawTiltX,
-        animationSpec = spring(dampingRatio = Spring.DampingRatioMediumBouncy, stiffness = Spring.StiffnessLow),
-        label = "tiltX"
-    )
-    val tiltY by animateFloatAsState(
-        targetValue = rawTiltY,
-        animationSpec = spring(dampingRatio = Spring.DampingRatioMediumBouncy, stiffness = Spring.StiffnessLow),
-        label = "tiltY"
-    )
 
     Box(
         modifier = modifier