feat(plugin-detail): show Markdown plugin details on bundle and market entry pages

Plugins bundle pages and Discover entry pages show the plugin's long
description first, as Markdown with images, in a height-limited region
without its own heading. The document is the file locale meta.detail
names, otherwise the package README, otherwise (market entries only)
the declared repository's README.

The new dsh-plugin-detail library selects documents and reads local
package directories and npm file CDNs without state. plugin-manager
reads installed and offered bundles through readBundleDetail; plugin-market
reads market entries through readEntryDetail, single-file APIs, and a
size-limited partial clone cache serialized across processes. Raw HTML is
omitted, relative links stay text, and relative images load from Host
routes with a sandbox CSP.

scripts/doc-standard.spec.ts

@@ -100,6 +100,7 @@ const PACKAGE_LIBRARIES: Readonly<Record<string, string>> = {
   'packages/util/native-command': 'Host-side subprocess runner utility.',
   'packages/util/output-retention': 'Zero-dependency retention utility.',
   'packages/util/package-manifest': 'Shared package manifest declarations with type-only exports.',
+  'packages/util/plugin-detail': 'Plugin detail document library.',
   'packages/util/plugin-market-index': 'Plugin market index validation library.',
   'packages/util/time': 'Zero-dependency time-zone canonicalization utility.',
   'packages/util/timeout': 'Zero-dependency timeout utility.',

scripts/gen-cordis-catalog.ts

@@ -309,6 +309,9 @@ export const LINK_MAP: Readonly<Record<string, string>> = {
   MarketQuery: 'boot.md',
   MarketSearchResult: 'boot.md',
   MarketSort: 'boot.md',
+  PluginDetail: 'boot.md',
+  BundleDetail: 'boot.md',
+  NpmFileSource: 'boot.md',
   ChangeResult: 'boot.md',
   InstallBundleOptions: 'boot.md',
   PluginEntryId: 'boot.md',

scripts/verify-package-readme-model-experience.ts

@@ -92,6 +92,7 @@ const SENTENCE_MODEL_EXPERIENCE: Readonly<Record<string, SentenceContract>> = {
   'packages/util/chunked-list': { kind: 'none', reason: 'Immutable collection primitive; registers nothing model-facing.' },
   'packages/util/package-manifest': { kind: 'none', reason: 'Type declarations only; registers nothing model-facing.' },
   'packages/util/lazy-require': { kind: 'none', reason: 'Host module-loading primitive; registers nothing model-facing.' },
+  'packages/util/plugin-detail': { kind: 'none', reason: 'Pure document selection for plugin detail pages; registers nothing model-facing.' },
   'packages/util/plugin-market-index': { kind: 'indirect', reason: 'Pure index validation; the plugin_market tool owns the entries it returns to the model.' },
   'packages/util/time': { kind: 'indirect', reason: 'Pure zone validation; the consumer that records a canonical zone owns the model-visible line derived from it.' },
   'packages/core/agent-default-model': { kind: 'indirect', reason: 'The service supplies a ModelSelection; request assembly and adapters own the model-visible request.' },