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/elements/ResourceLinkInfo/ResourceLinkInfo.tsx

@@ -0,0 +1,90 @@
+import type { ReactNode } from "react";
+import { Badge, Group, Stack, Text } from "@mantine/core";
+
+export interface ResourceLinkInfoProps {
+  /** The linked resource's URI (always shown). */
+  uri: string;
+  /** Optional human-friendly name shown beneath the URI. */
+  name?: string;
+  /** Optional description shown beneath the name. */
+  description?: string;
+  /** Optional MIME type shown as a badge. */
+  mimeType?: string;
+  /**
+   * Optional trailing element placed at the end of the URI row — e.g. an
+   * expand/collapse indicator supplied by an interactive wrapper.
+   */
+  action?: ReactNode;
+}
+
+const HeaderStack = Stack.withProps({
+  gap: 4,
+});
+
+const UriRow = Group.withProps({
+  justify: "space-between",
+  wrap: "nowrap",
+  gap: "xs",
+  align: "flex-start",
+});
+
+const UriText = Text.withProps({
+  size: "sm",
+  c: "blue",
+  ff: "monospace",
+  variant: "monoBreak",
+  flex: 1,
+  miw: 0,
+});
+
+const MetaGroup = Group.withProps({
+  gap: "xs",
+  wrap: "nowrap",
+});
+
+const MimeBadge = Badge.withProps({
+  size: "sm",
+  variant: "light",
+  color: "blue",
+  // MIME types are conventionally lowercase; keep them as-is rather than
+  // letting Badge's default uppercase transform mangle them.
+  tt: "none",
+});
+
+const NameText = Text.withProps({
+  size: "sm",
+  fw: 600,
+});
+
+const DescriptionText = Text.withProps({
+  size: "sm",
+  c: "dimmed",
+});
+
+/**
+ * Pure-display metadata for a `resource_link`: the URI (monospace, link-styled),
+ * optional name / description, and a MIME-type badge. The optional `action`
+ * slot lets an interactive wrapper (e.g. {@link ResourceLink}) place an
+ * expand/collapse indicator in the URI row.
+ */
+export function ResourceLinkInfo({
+  uri,
+  name,
+  description,
+  mimeType,
+  action,
+}: ResourceLinkInfoProps) {
+  return (
+    <HeaderStack>
+      <UriRow>
+        <UriText>{uri}</UriText>
+        <MetaGroup>
+          {mimeType && <MimeBadge>{mimeType}</MimeBadge>}
+          {action}
+        </MetaGroup>
+      </UriRow>
+      {name && <NameText>{name}</NameText>}
+      {description && <DescriptionText>{description}</DescriptionText>}
+    </HeaderStack>
+  );
+}