Phase 2: Refactor Prompts cluster to MCP SDK types

Replace ad hoc local types with MCP SDK schema types across the Prompts
group components and PromptsScreen, per the v2 UX interfaces plan.

- PromptListItem: accept `prompt: Prompt` instead of flat `name`/`description`;
  render `title ?? name` as primary label
- PromptControls: accept `Prompt[]` + `selectedName` instead of `PromptItem[]`;
  no-op on clicking already-selected prompt; search includes title field
- PromptArgumentsForm: accept `prompt: Prompt` instead of flat props;
  read `prompt.arguments` directly; display `title ?? name` as heading
- PromptMessagesDisplay: narrow type from `(PromptMessage | SamplingMessage)[]`
  to `PromptMessage[]` per spec
- PromptsScreen: accept `Prompt[]` + `selectedPromptName` + `GetPromptState`;
  derive selected prompt via `prompts.find()`; own `argumentValues` state
  locally; reset arguments on tool switch
- Delete local `PromptItem`, `SelectedPrompt`, `PromptArgument` types
- Update all stories with real SDK `Prompt` fixtures
- Update ConnectedView PromptsActive story

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

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

@@ -15,23 +15,40 @@ type Story = StoryObj<typeof PromptListItem>;
 
 export const Default: Story = {
   args: {
-    name: "summarize",
-    description: "Summarize the given text into key points",
+    prompt: {
+      name: "summarize",
+      description: "Summarize the given text into key points",
+    },
     selected: false,
   },
 };
 
 export const Selected: Story = {
   args: {
-    name: "translate",
-    description: "Translate text from one language to another",
+    prompt: {
+      name: "translate",
+      description: "Translate text from one language to another",
+    },
     selected: true,
   },
 };
 
+export const WithTitle: Story = {
+  args: {
+    prompt: {
+      name: "code-review",
+      title: "Code Review",
+      description: "Review code for issues and best practices",
+    },
+    selected: false,
+  },
+};
+
 export const NoDescription: Story = {
   args: {
-    name: "code-review",
+    prompt: {
+      name: "code-review",
+    },
     selected: false,
   },
 };

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

@@ -1,8 +1,8 @@
 import { Stack, Text, UnstyledButton } from "@mantine/core";
+import type { Prompt } from "@modelcontextprotocol/sdk/types.js";
 
 export interface PromptListItemProps {
-  name: string;
-  description?: string;
+  prompt: Prompt;
   selected: boolean;
   onClick: () => void;
 }
@@ -18,11 +18,11 @@ const DescriptionText = Text.withProps({
 });
 
 export function PromptListItem({
-  name,
-  description,
+  prompt,
   selected,
   onClick,
 }: PromptListItemProps) {
+  const { name, title, description } = prompt;
   return (
     <UnstyledButton
       w="100%"
@@ -32,7 +32,7 @@ export function PromptListItem({
       onClick={onClick}
     >
       <Stack gap={2}>
-        <NameText>{name}</NameText>
+        <NameText>{title ?? name}</NameText>
         {description && <DescriptionText>{description}</DescriptionText>}
       </Stack>
     </UnstyledButton>