feat(components): step progress for the onboarding scaffold

A multi-step flow passes a progress slot, pinned above the scrolling
content, and OnboardingProgress draws it as one capsule per step with the
caller's own localised label. topSpacing lets a step whose hero is a large
picture rather than a mark keep the content on one screen.

components/src/main/kotlin/de/jeanlucmakiola/floret/components/Onboarding.kt

@@ -1,5 +1,6 @@
 package de.jeanlucmakiola.floret.components
 
+import androidx.compose.animation.animateColorAsState
 import androidx.compose.foundation.background
 import androidx.compose.foundation.layout.Arrangement
 import androidx.compose.foundation.layout.Box
@@ -13,6 +14,7 @@ import androidx.compose.foundation.layout.height
 import androidx.compose.foundation.layout.navigationBarsPadding
 import androidx.compose.foundation.layout.padding
 import androidx.compose.foundation.layout.size
+import androidx.compose.foundation.layout.statusBarsPadding
 import androidx.compose.foundation.layout.width
 import androidx.compose.foundation.rememberScrollState
 import androidx.compose.foundation.shape.CircleShape
@@ -22,10 +24,13 @@ import androidx.compose.material3.MaterialTheme
 import androidx.compose.material3.Scaffold
 import androidx.compose.material3.Text
 import androidx.compose.runtime.Composable
+import androidx.compose.runtime.getValue
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.draw.clip
 import androidx.compose.ui.graphics.vector.ImageVector
+import androidx.compose.ui.semantics.clearAndSetSemantics
+import androidx.compose.ui.unit.Dp
 import androidx.compose.ui.unit.dp
 
 /** MD3 8dp spacing scale shared by the onboarding screens. */
@@ -43,17 +48,35 @@ object OnboardingSpace {
  * bar). The content slot is centred horizontally; benefit rows fill the width so
  * their own content left-aligns. Each app supplies its own hero so the apps read
  * as one family while keeping their own mark.
+ *
+ * A multi-step flow passes [progress] (see [OnboardingProgress]), which is
+ * pinned above the scrolling content. [topSpacing] gives a step whose hero is a
+ * large picture rather than a mark room to breathe without overflowing.
  */
 @Composable
 fun OnboardingScaffold(
     hero: @Composable () -> Unit,
     actions: @Composable ColumnScope.() -> Unit,
     modifier: Modifier = Modifier,
+    progress: (@Composable () -> Unit)? = null,
+    topSpacing: Dp = OnboardingSpace.xl,
     body: @Composable ColumnScope.() -> Unit,
 ) {
     Scaffold(
         modifier = modifier,
         containerColor = MaterialTheme.colorScheme.surface,
+        topBar = {
+            if (progress != null) {
+                Box(
+                    modifier = Modifier
+                        .fillMaxWidth()
+                        .statusBarsPadding()
+                        .padding(horizontal = OnboardingSpace.md, vertical = OnboardingSpace.sm),
+                ) {
+                    progress()
+                }
+            }
+        },
         bottomBar = {
             Column(
                 modifier = Modifier
@@ -74,7 +97,7 @@ fun OnboardingScaffold(
                 .padding(horizontal = OnboardingSpace.md),
             horizontalAlignment = Alignment.CenterHorizontally,
         ) {
-            Spacer(Modifier.height(OnboardingSpace.xl))
+            Spacer(Modifier.height(topSpacing))
             hero()
             Spacer(Modifier.height(OnboardingSpace.lg))
             body()
@@ -83,6 +106,60 @@ fun OnboardingScaffold(
     }
 }
 
+/**
+ * Where a multi-step onboarding flow has got to: one capsule per step, filled up
+ * to and including [step] (1-based), with [label] — the caller's own localised
+ * "Step 2 of 4" — underneath.
+ *
+ * The capsules carry no semantics of their own; [label] is the accessible
+ * description, so a screen reader hears the position once rather than counting
+ * decorations.
+ */
+@Composable
+fun OnboardingProgress(
+    step: Int,
+    total: Int,
+    label: String,
+    modifier: Modifier = Modifier,
+) {
+    Column(
+        modifier = modifier.fillMaxWidth(),
+        horizontalAlignment = Alignment.CenterHorizontally,
+    ) {
+        Row(
+            modifier = Modifier
+                .fillMaxWidth()
+                .clearAndSetSemantics { },
+            horizontalArrangement = Arrangement.spacedBy(4.dp),
+        ) {
+            repeat(total) { index ->
+                val done = index < step
+                val color by animateColorAsState(
+                    targetValue = if (done) {
+                        MaterialTheme.colorScheme.primary
+                    } else {
+                        MaterialTheme.colorScheme.surfaceContainerHighest
+                    },
+                    label = "onboarding-progress-segment",
+                )
+                Box(
+                    modifier = Modifier
+                        .weight(1f)
+                        .height(4.dp)
+                        .clip(CircleShape)
+                        .background(color),
+                )
+            }
+        }
+        Spacer(Modifier.height(OnboardingSpace.xs))
+        Text(
+            text = label,
+            style = MaterialTheme.typography.labelMedium,
+            color = MaterialTheme.colorScheme.onSurfaceVariant,
+        )
+    }
+}
+
 /** One trust point: a tonal icon chip on the left, title + supporting text right. */
 @Composable
 fun BenefitRow(icon: ImageVector, title: String, body: String) {