feat(web): expandable resource_link with read-on-demand (#1449) (#1456)

* feat(web): expandable resource_link with read-on-demand (#1449)

Replace the placeholder `resource_link` rendering in ContentViewer with a
dedicated, Mantine-native `ResourceLink` element that mirrors V1's behavior:

- Shows uri (monospace, link-styled), optional name/description, and a
  mimeType badge.
- Expand/collapse affordance (chevron + loading spinner) that is keyboard
  accessible (native button: role, aria-expanded, aria-label, Enter/Space).
- On first expand, reads the linked resource on demand via an injected
  callback and renders the full read result inline as formatted JSON under a
  green "Resource:" label, capped to a max height with scroll for large
  results. The fetched result is cached across collapse/expand.

The read handler is threaded as a "dumb component + callback as prop" through
ToolResultPanel → ToolsScreen → InspectorView, with App supplying a handler
that returns the `ReadResourceResult` from `inspectorClient.readResource`.

Also extract the shared `resourceContentsToBlock` helper into
`utils/resourceContents.ts` (previously private to ResourcePreviewPanel).

Tests: unit coverage for ResourceLink (collapsed/expanded/error/cache) and
the ContentViewer wiring, plus Storybook stories with play functions.

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

* fix(web): scroll large resource_link read results within the card

A plain ScrollArea with only `mah` does not scroll when its parent (the
content-sized card) has no definite height, so a large read result overflowed
the card instead of scrolling. Switch to ScrollArea.Autosize, which grows with
content up to the max height and then scrolls. Adds a LargeResult story
covering the bounded-scroll behavior.

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

* refactor(web): make ResourceLink a group; extract ResourceLinkInfo element

ResourceLink is stateful (expand/loading/cached result) and fetches data via
a callback — group-like behavior, and the only `elements/` component using
useState. Move it to `groups/` and split out the pure-display metadata as a
new `elements/ResourceLinkInfo` element (uri/name/description/mime + an
optional action slot).

This keeps the layer dependencies clean (no element→group import, which
moving ResourceLink alone would have introduced):
- ContentViewer (element) renders ResourceLinkInfo (element) statically for
  `resource_link` blocks and no longer takes an onReadResource prop.
- ToolResultPanel (group) renders the interactive ResourceLink (group) for
  `resource_link` blocks, ContentViewer for the rest.
- ResourceLink (group) composes ResourceLinkInfo + ContentViewer.

Also reverts the now-single-consumer resourceContents.ts extraction, restoring
ResourcePreviewPanel's local toContentBlock.

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

* fix(web): make ResourceLink read retryable and guard double-fetch

Address PR review: a failed read is no longer cached as terminal — only
a successful result is cached, so collapsing and re-expanding retries the
read after a transient failure. Add a loading guard so toggling while a
read is in flight does not fire a redundant second read.

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

* style(web): prettier formatting for ResourceLink test

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

* chore: remove accidentally-committed build artifacts; gitignore clients/*/build

A stray 'git add -A' swept 8 compiled build files into d25c9382. Remove
them from tracking and add clients/*/build to .gitignore so client build
output is never committed again.

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

---------

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

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

@@ -7,12 +7,21 @@ import {
   Text,
   Title,
 } from "@mantine/core";
-import type { CallToolResult } from "@modelcontextprotocol/sdk/types.js";
+import type {
+  CallToolResult,
+  ReadResourceResult,
+} from "@modelcontextprotocol/sdk/types.js";
 import { ContentViewer } from "../../elements/ContentViewer/ContentViewer";
+import { ResourceLink } from "../ResourceLink/ResourceLink";
 
 export interface ToolResultPanelProps {
   result: CallToolResult;
   onClear: () => void;
+  /**
+   * Read-on-demand handler so `resource_link` blocks in the result can fetch
+   * and inline their contents.
+   */
+  onReadResource?: (uri: string) => Promise<ReadResourceResult>;
 }
 
 const ClearButton = Button.withProps({
@@ -49,7 +58,11 @@ const ResultStack = Stack.withProps({
   gap: "md",
 });
 
-export function ToolResultPanel({ result, onClear }: ToolResultPanelProps) {
+export function ToolResultPanel({
+  result,
+  onClear,
+  onReadResource,
+}: ToolResultPanelProps) {
   return (
     <PanelStack>
       <HeaderRow>
@@ -68,13 +81,24 @@ export function ToolResultPanel({ result, onClear }: ToolResultPanelProps) {
           ) : result.content.length === 0 ? (
             <Text c="dimmed">No results yet</Text>
           ) : (
-            result.content.map((block, index) => (
-              <ContentViewer
-                key={index}
-                block={block}
-                copyable={block.type === "text"}
-              />
-            ))
+            result.content.map((block, index) =>
+              block.type === "resource_link" ? (
+                <ResourceLink
+                  key={index}
+                  uri={block.uri}
+                  name={block.name}
+                  description={block.description}
+                  mimeType={block.mimeType}
+                  onReadResource={onReadResource}
+                />
+              ) : (
+                <ContentViewer
+                  key={index}
+                  block={block}
+                  copyable={block.type === "text"}
+                />
+              ),
+            )
           )}
         </ResultStack>
       </ResultScroll>