feat(components): let picker content own its scrolling

CollapsingScaffold always wrapped its content in a verticalScroll Column,
which composes every row up front. That suits the short lists these
surfaces normally hold, but it rules out a LazyColumn entirely: nesting a
same-axis scrollable inside it throws, so a caller with a few hundred
options had no way to render them.

Add `scrollable` (default true, so every existing caller is unchanged).
When false the content gets a plain column to fill and brings its own
scrolling container, keeping the insets, IME padding and top-bar collapse
as they were. FullScreenPicker forwards the flag for pickers that need it.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

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

@@ -46,6 +46,16 @@ import de.jeanlucmakiola.floret.identity.predictiveBack
  * unchanged: [actions] adds trailing app-bar items; [snackbarHost] hosts
  * transient messages; [predictiveBack] (off by default) wires the gesture
  * preview to [onBack] for full-screen surfaces that want it.
+ *
+ * Set [scrollable] to false when [content] brings its own scrolling container.
+ * The default column scrolls as a whole, which composes every row up front —
+ * fine for the short lists these surfaces normally hold, but a list long enough
+ * to need a [androidx.compose.foundation.lazy.LazyColumn] can neither nest one
+ * inside it (same-axis scrolling throws) nor afford the eager pass. Opting out
+ * hands [content] a plain, unscrolled column to fill instead; the insets, IME
+ * padding and bar behaviour are unchanged, so a lazy list simply takes over the
+ * scrolling and gets the top bar's collapse for free through the shared
+ * nested-scroll connection.
  */
 @OptIn(ExperimentalMaterial3Api::class)
 @Composable
@@ -55,6 +65,7 @@ fun CollapsingScaffold(
     modifier: Modifier = Modifier,
     largeTopBar: Boolean = true,
     predictiveBack: Boolean = false,
+    scrollable: Boolean = true,
     actions: @Composable RowScope.() -> Unit = {},
     snackbarHost: @Composable () -> Unit = {},
     content: @Composable ColumnScope.() -> Unit,
@@ -112,8 +123,19 @@ fun CollapsingScaffold(
                 .fillMaxSize()
                 .background(MaterialTheme.colorScheme.surface)
                 .imePadding()
-                .verticalScroll(rememberScrollState())
-                .padding(top = 8.dp, bottom = 24.dp),
+                .then(
+                    if (scrollable) {
+                        Modifier
+                            .verticalScroll(rememberScrollState())
+                            .padding(top = 8.dp, bottom = 24.dp)
+                    } else {
+                        // The content scrolls itself, so it also owns the edge
+                        // spacing — a lazy list wants it as contentPadding, or
+                        // the first and last rows clip instead of scrolling
+                        // under the bars.
+                        Modifier
+                    },
+                ),
             content = content,
         )
     }

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

@@ -20,12 +20,17 @@ import androidx.compose.ui.window.DialogWindowProvider
  * width without a tall header — it's a short selection list, so the large
  * collapsing header would only be empty space to scroll past. [content] places
  * the connected grouped rows; selecting one calls [onDismiss].
+ *
+ * [scrollable] forwards to [CollapsingScaffold]: leave it on unless [content]
+ * scrolls itself, which a picker only needs for an option list long enough to
+ * warrant a lazy container.
  */
 @Composable
 fun FullScreenPicker(
     title: String,
     onDismiss: () -> Unit,
     predictiveBack: Boolean = false,
+    scrollable: Boolean = true,
     actions: @Composable RowScope.() -> Unit = {},
     content: @Composable ColumnScope.() -> Unit,
 ) {
@@ -50,6 +55,7 @@ fun FullScreenPicker(
             onBack = onDismiss,
             largeTopBar = false,
             predictiveBack = predictiveBack,
+            scrollable = scrollable,
             actions = actions,
             content = content,
         )