fix(layout): keep chat transcript region full-height when empty (composer pinned to bottom)

1 files changed, 7 insertions, 1 deletions

diff --git a/src/features/layout/ui/TileStack.svelte b/src/features/layout/ui/TileStack.svelte
index 13dab09..ac7091a 100644
--- a/src/features/layout/ui/TileStack.svelte
+++ b/src/features/layout/ui/TileStack.svelte
@@ -3,6 +3,12 @@
    * A plain vertical container (today's left column). `grow` children flex
    * (`flex: grow 1 0%` — the chat region scrolls internally, exactly like
    * today's `flex-1`); children without grow take natural height.
+   *
+   * `h-full` keeps the container's main size DEFINITE (the parent is the
+   * split-child wrapper, cross-stretched to the full-height split row). With
+   * an indefinite height, `flex: 1 1 0%` degenerates to content sizing — an
+   * EMPTY grow child collapses to ~0 and the siblings below it (composer)
+   * ride to the top instead of staying pinned at the bottom.
    */
   import type { LayoutOp, Path, StackNode } from "@dispatch/layout-contract";
   import type { CollapseStore } from "../logic/collapse";
@@ -23,7 +29,7 @@
   } = $props();
 </script>
 
-<div class="flex min-h-0 min-w-0 flex-col overflow-hidden">
+<div class="flex h-full min-h-0 min-w-0 flex-col overflow-hidden">
   {#each node.children as child, i (i)}
     <div class="min-h-0 min-w-0" style={"flex: " + (child.grow ?? 0) + (child.grow === undefined ? " 0 auto" : " 1 0%")}>
       <TileNode node={child.node} path={[...path, i]} {ports} {collapse} {onEdit} />