fix(web): make sidebar lists, monitor panels, and Tools placeholder fill height (#1663) (#1664)

Three related "fill the available height" layout fixes to the connected screens:

- Tools & Prompts sidebars: replace the fixed magic max-height on ToolControls/
  PromptControls with the Resources pattern — sidebar Card `variant="sidebar"`
  (full-height flex column) + `Stack flex={1} mih={0}` + a flex-filling
  ScrollArea — so the list runs to the bottom of the card before scrolling.
- Logs/Console/Protocol/Network standalone screens: only override ScreenLayout
  `h` when embedded. Passing `h={undefined}` clobbered the default
  `h: calc(100dvh - header)` (withProps plain-spreads), collapsing an empty
  screen to its controls' height. Also center the Network/Protocol empty states.
- Tools placeholder: render the "Select a tool" empty state in a full-height
  `DetailCard flex={1}` (like Prompts/Resources) instead of the content-sized
  preview card, so it fills the pane.


Claude-Session: https://claude.ai/code/session_015sMW1YZXkM7fDkdPtHpE95

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

clients/web/src/components/groups/NetworkStreamPanel/NetworkStreamPanel.tsx

@@ -34,10 +34,17 @@ const PanelContainer = Paper.withProps({
   variant: "panel",
 });
 
+// Centered in the full-height panel so the empty message sits mid-panel rather
+// than clinging to the top of an otherwise-empty box (matches LogStreamPanel).
+const EmptyCenter = Stack.withProps({
+  flex: 1,
+  align: "center",
+  justify: "center",
+});
+
 const EmptyState = Text.withProps({
   c: "dimmed",
   ta: "center",
-  py: "xl",
 });
 
 function formatTitle(count: number): string {
@@ -133,7 +140,9 @@ export function NetworkStreamPanel({
       </Group>
 
       {!hasResults ? (
-        <EmptyState>No network requests</EmptyState>
+        <EmptyCenter>
+          <EmptyState>No network requests</EmptyState>
+        </EmptyCenter>
       ) : (
         <EmbeddableScrollArea
           embedded={embedded}

clients/web/src/components/groups/PromptControls/PromptControls.tsx

@@ -17,9 +17,6 @@ export interface PromptControlsProps {
   onSelectPrompt: (name: string) => void;
 }
 
-const LIST_MAX_HEIGHT =
-  "calc(100vh - var(--app-shell-header-height, 0px) - var(--mantine-spacing-xl) * 2 - 160px)";
-
 export function PromptControls({
   prompts,
   selectedName,
@@ -39,7 +36,10 @@ export function PromptControls({
   );
 
   return (
-    <Stack gap="sm">
+    // Fill the full-height `sidebar` Card (a flex column) so the list runs to the
+    // bottom of the card before it scrolls, instead of being capped short by a
+    // fixed max-height. `mih: 0` lets the scroll child shrink and scroll.
+    <Stack gap="sm" flex={1} mih={0}>
       <Group justify="space-between">
         <Title order={4}>Prompts</Title>
         <ListChangedIndicator visible={listChanged} onRefresh={onRefreshList} />
@@ -53,7 +53,7 @@ export function PromptControls({
           searchText ? <ClearButton onClick={() => onSearchChange("")} /> : null
         }
       />
-      <ScrollArea.Autosize viewportRef={viewportRef} mah={LIST_MAX_HEIGHT}>
+      <ScrollArea viewportRef={viewportRef} flex={1} mih={0} type="auto">
         <Stack gap="xs">
           {filteredPrompts.map((prompt) => (
             <PromptListItem
@@ -66,7 +66,7 @@ export function PromptControls({
             />
           ))}
         </Stack>
-      </ScrollArea.Autosize>
+      </ScrollArea>
     </Stack>
   );
 }

clients/web/src/components/groups/ProtocolListPanel/ProtocolListPanel.tsx

@@ -54,10 +54,17 @@ const PanelContainer = Paper.withProps({
   variant: "panel",
 });
 
+// Centered in the full-height panel so the empty message sits mid-panel rather
+// than clinging to the top of an otherwise-empty box (matches LogStreamPanel).
+const EmptyCenter = Stack.withProps({
+  flex: 1,
+  align: "center",
+  justify: "center",
+});
+
 const EmptyState = Text.withProps({
   c: "dimmed",
   ta: "center",
-  py: "xl",
 });
 
 // The section header is a single "pleat" bar (rounded, with the filter-button
@@ -293,7 +300,9 @@ export function ProtocolListPanel({
       </Group>
 
       {!hasResults ? (
-        <EmptyState>No request history</EmptyState>
+        <EmptyCenter>
+          <EmptyState>No request history</EmptyState>
+        </EmptyCenter>
       ) : (
         <EmbeddableScrollArea embedded={embedded} viewportRef={viewportRef}>
           <Stack gap="md">

clients/web/src/components/groups/ToolControls/ToolControls.tsx

@@ -17,9 +17,6 @@ export interface ToolControlsProps {
   onSelectTool: (name: string) => void;
 }
 
-const LIST_MAX_HEIGHT =
-  "calc(100vh - var(--app-shell-header-height, 0px) - var(--mantine-spacing-xl) * 2 - 160px)";
-
 export function ToolControls({
   tools,
   selectedName,
@@ -40,7 +37,12 @@ export function ToolControls({
     : tools;
 
   return (
-    <Stack gap="sm">
+    // Fill the full-height `sidebar` Card (a flex column) so the scroll region
+    // below claims all the remaining space under the fixed title/search — the
+    // list runs to the bottom of the card before it scrolls, instead of being
+    // capped short by a fixed max-height. `mih: 0` lets the scroll child shrink
+    // and scroll rather than overflow the card.
+    <Stack gap="sm" flex={1} mih={0}>
       <Group justify="space-between">
         <Title order={4}>Tools</Title>
         <ListChangedIndicator visible={listChanged} onRefresh={onRefreshList} />
@@ -54,7 +56,7 @@ export function ToolControls({
           searchText ? <ClearButton onClick={() => onSearchChange("")} /> : null
         }
       />
-      <ScrollArea.Autosize viewportRef={viewportRef} mah={LIST_MAX_HEIGHT}>
+      <ScrollArea viewportRef={viewportRef} flex={1} mih={0} type="auto">
         <Stack gap="xs">
           {filteredTools.map((tool) => (
             <ToolListItem
@@ -67,7 +69,7 @@ export function ToolControls({
             />
           ))}
         </Stack>
-      </ScrollArea.Autosize>
+      </ScrollArea>
     </Stack>
   );
 }