feat(apps): render tool.icons on ToolListItem and ToolDetailPanel (#1264) (#1293)

* feat(apps): render tool.icons on ToolListItem (#1264)

Add icon rendering to ToolListItem so the Tools sidebar matches the
Apps sidebar treatment. Falls back gracefully when tool.icons is absent.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

* fix(stories): use #228be6 in ToolListItem WithIcon data URL

The source SVG had %23228be6 pre-encoded, but encodeURIComponent then
re-escaped the % to %25, leaving fill="%23228be6" in the decoded SVG
and making the icon render black instead of Mantine blue.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

* feat(apps): render tool.icons on ToolDetailPanel (#1264)

Show the tool icon next to the title in the detail panel, matching the
header icon size used in AppsScreen (24x24, fit: contain). Adds a
WithIcon story and tests for icon-present/icon-absent states.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

clients/web/src/components/groups/ToolDetailPanel/ToolDetailPanel.stories.tsx

@@ -71,6 +71,26 @@ const longQueryTool: Tool = {
   },
 };
 
+const ICON_DATA_URL =
+  "data:image/svg+xml;utf8," +
+  encodeURIComponent(
+    '<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24" fill="#228be6"><circle cx="12" cy="12" r="10"/></svg>',
+  );
+
+const iconedTool: Tool = {
+  name: "send_message",
+  title: "Send Message",
+  description: "Sends a message to the recipient",
+  icons: [{ src: ICON_DATA_URL }],
+  inputSchema: {
+    type: "object",
+    properties: {
+      message: { type: "string", description: "The message to send" },
+    },
+    required: ["message"],
+  },
+};
+
 const batchProcessTool: Tool = {
   name: "batch_process",
   description: "Processes items in batch",
@@ -94,6 +114,12 @@ export const MultipleParams: Story = {
   },
 };
 
+export const WithIcon: Story = {
+  args: {
+    tool: iconedTool,
+  },
+};
+
 export const WithAnnotations: Story = {
   args: {
     tool: deleteRecordsTool,