feat(dsh): adapt to DSH 0.1.5-alpha.2

Baseline moves to DSH 0.1.5-alpha.2 only (peer floor ^0.1.5-alpha.2,
CI pin, manifest engines); alpha.1 users stay on v0.19.0-alpha.0.

Host-contract changes handled:
- the native guide entry lost its `description` field (entries are
  icon+title capsules now): `TabDescriptor.description` and the six
  `guideDesc*` keys plus the `nativeGuideDesc` fallback are removed.
- the file address grammar changed: `fileAddressFor` always returns a
  session-scoped address (absolute paths keep their leading `/`),
  `parseFileAddress` is prefix-based and strips `?`/`#`. The plugin's
  purity-gated mirror follows.
- global main panels replaced the `conversation` root slot with the
  keyed `main` slot (`main.conversation`): the bottom workbench's
  center-column locator now accepts both keys and skips
  `display: contents` slot hosts.

Fixes a pre-existing fill bug the alpha.2 probe made obvious: the native
tab body host is a block scroller with a definite height, so tab roots
that only declared `flex: 1` collapsed to content height and the side
chat composer drifted off the pane bottom. The native adapter now wraps
every tab body in a `height: 100%` column flex host.

Also promotes the dependencies `dsh-client-ui-primitives@0.1.5-alpha.2`
dropped from its manifest (anser / shiki / mdast-util-* / micromark-* /
katex / @shikijs/langs) and the newly unmet `dsh-session-persistence`
peer into devDependencies.

src/client/native/index.ts

@@ -43,7 +43,7 @@ interface NativeTabRegistry {
     priority?: 'extension' | 'builtin' | 'fallback'
     canOpen?: (address: string) => boolean
     title: (address: string) => string
-    guide?: readonly { order: number; title: () => string; description: () => string; icon?: unknown }[]
+    guide?: readonly { order: number; title: () => string; icon?: unknown }[]
   }): () => void
 }
 
@@ -63,17 +63,6 @@ function titleOf(descriptor: TabDescriptor): string {
   return typeof descriptor.title === 'function' ? descriptor.title() : descriptor.title
 }
 
-/**
- * The descriptor's guide line, evaluated fresh for the current locale. The
- * host's new-tab list renders one line per entry; without a declared
- * description every plugin page would read the same generic sentence.
- */
-function descriptionOf(descriptor: TabDescriptor | undefined): string {
-  const description = descriptor?.description
-  if (description === undefined) return t('nativeGuideDesc')
-  return typeof description === 'function' ? description() : description
-}
-
 /**
  * The guide row's glyph for a descriptor icon (nothing when it has none).
  * The native guide renders `entry.icon`, so a takeover registered without one
@@ -192,7 +181,6 @@ export function registerNativeSurface(deps: NativeSurfaceDeps): () => void {
             guide: [{
               order: descriptor.order ?? 100,
               title: () => titleOf(descriptor),
-              description: () => descriptionOf(descriptor),
               ...guideIconOf(icon),
             }],
           }),
@@ -219,7 +207,6 @@ export function registerNativeSurface(deps: NativeSurfaceDeps): () => void {
         guide: [{
           order: 10,
           title: () => t('files'),
-          description: () => descriptionOf(editor),
           // The takeover IS the editor descriptor's page, so it carries the
           // editor's glyph: without it the "Files" row is the only guide
           // entry with an empty icon slot.

src/client/native/tab-adapter.tsx

@@ -281,33 +281,49 @@ export function NativeTabBody(props: NativeBodyInjected & NativeBodyFrameworkPro
   })
   useEffect(() => () => { records.drop(nativeTab.id) }, [records, nativeTab.id])
   if (descriptor === undefined) {
-    return createElement(OrphanedTab, { ctx, store, scope, tab: view.tab, visible: nativeTab.visible })
+    // The orphaned fallback sits in the SAME native host as a live body, so
+    // it gets the same full-height box (its own root also relies on the
+    // `flex: 1` contract the column host restores). The host div carries
+    // `data-dsh-native-tab-host` (empty value) so the e2e lane can assert
+    // the fill, mirroring `data-dsh-better-sidebar`.
+    return createElement(
+      'div',
+      { className: css.nativeTabHost, 'data-dsh-native-tab-host': '' },
+      createElement(OrphanedTab, { ctx, store, scope, tab: view.tab, visible: nativeTab.visible }),
+    )
   }
   return createElement(
     RenderBoundary,
     { className: css.tabBoundaryError },
-    createElement(descriptor.component, {
-      ctx,
-      store,
-      scope,
-      tab: view.tab,
-      visible: nativeTab.visible,
-      expanded: view.expanded,
-      revealed: view.revealed,
-      onToggleDir: (path: string) => { records.toggleExpanded(nativeTab.id, path) },
-      onReferenceFile: (path: string, isDir: boolean) => { referenceInChat(ctx, sessionId, cwd, path, isDir) },
-      onOpenDiff: (tab: SidebarTab) => {
-        service.openTab({
-          type: 'diff',
-          title: tab.title,
-          id: tab.id,
-          ...(tab.diff === undefined ? {} : { diff: tab.diff }),
-        }, scope)
-      },
-      onSubagentJump: (childSessionId: string) => {
-        service.openTab({ type: 'subagent', meta: { childSessionId } }, scope)
-      },
-    }),
+    // The full-height host wrapper (see the `.nativeTabHost` rule in
+    // sidebar.module.css for the native `.paneBody` contract); its
+    // `data-dsh-native-tab-host` attribute lets the e2e lane assert the fill.
+    createElement(
+      'div',
+      { className: css.nativeTabHost, 'data-dsh-native-tab-host': '' },
+      createElement(descriptor.component, {
+        ctx,
+        store,
+        scope,
+        tab: view.tab,
+        visible: nativeTab.visible,
+        expanded: view.expanded,
+        revealed: view.revealed,
+        onToggleDir: (path: string) => { records.toggleExpanded(nativeTab.id, path) },
+        onReferenceFile: (path: string, isDir: boolean) => { referenceInChat(ctx, sessionId, cwd, path, isDir) },
+        onOpenDiff: (tab: SidebarTab) => {
+          service.openTab({
+            type: 'diff',
+            title: tab.title,
+            id: tab.id,
+            ...(tab.diff === undefined ? {} : { diff: tab.diff }),
+          }, scope)
+        },
+        onSubagentJump: (childSessionId: string) => {
+          service.openTab({ type: 'subagent', meta: { childSessionId } }, scope)
+        },
+      }),
+    ),
   )
 }