chore(sync): re-base the fork onto upstream dsh-better-sidebar v0.19.1

The fork was pinned at upstream v0.18.0. That is the entire reason the window
ran TWO sidebars and TWO near-identical panel toggles: DSH 2.0.10 ships its own
right sidebar (@deepseek-ai/dsh-client-ui-sidebar-right), and upstream only
adopted it in v0.19.0-alpha.1 — which arrived after our fork point. v0.19.1 is
also the one upstream line whose support range actually matches our host
(engines.dsh >=0.1.5-rc.1, 14 DSH peers ^0.1.5-rc.1, host = 0.1.5-rc.2), so it
is the only tag the host's startup precheck accepts.

What upstream v0.18.0 → v0.19.1 brings
- src/client/native/{index,surface,tab-adapter}.tsx: every tab the plugin can
  draw becomes an OFFICIAL native tab type + body, and an external plugin's
  descriptor registered later gets its native type too. This is what retires
  the fork's own right panel — and with it the duplicate toggle cluster
  (`toggleCluster` is gone from v0.19.1).
- native tab-chip icons via the `sidebar.right.pane.tab.title` seat, coloured
  built-in tab icons, file/folder glyphs from DSH's own `FileTypeIcon`.
- guide descriptions (DSH renders them while the guide lists <= 4 entries),
  tab bodies that fill the panel, and the 0.1.5-rc.2 adaptation work we were
  carrying by hand (peer/devDep pinning, primitives' transitive devDeps).

How the sync was done
Rebuilt the tree from the v0.19.1 tag rather than resolving 53 conflicted
files: our v0.18.0 delta was measured first and is only (a) one mechanical
rename `dsh-better-sidebar` -> `dsh-apes-sidebar` and (b) ten real edits. So:
tag tree + rename (scoped: code/config/scripts/tests/README, while the 46
historical docs/plans records and switch.sh's upstream package name stay
untouched) + re-applied deltas + our apes module.

Fork deltas re-applied on the new base
- src/client/apes/ (icons / locales / tabs): the three apes:* information-layer
  tabs (agents / apps / profile), registered through the same BetterSidebarService
  as the builtins — which is exactly why they now ride upstream's native adapter
  into the official sidebar for free.
- identity: package.json (name/version 1.2.0/description/forkedFrom), dsh.plugin.json
  (id/version), SIDEBAR_SERVICE_VERSION 1.2.0, README fork notice,
  docs/external-plugin-guide.md.
- scripts/switch.sh + the pnpm switch* scripts (apes <-> upstream two-line switch).
- tests/apes-tabs.spec.ts (unescaped: it starts from the v0.19.1 base).

Dropped
- the Phase A native-registration spike (`apes/native-tabs.tsx` + its spec): it
  re-derived by hand exactly what upstream's native layer already does — the
  hand-written bridge is dead weight now, and v0.19.1's own e2e/jsdom lanes
  cover the same seat contract far better.
- the unused apesProfileGuideDesc key and the two package.json.bak.* backups.

Verified on the new base: typecheck clean; build clean; 1351 passed / 9 skipped
(128 files), up from 1255 on the old base.

tests/plugin-shape.spec.ts

@@ -8,7 +8,7 @@ import * as sidebar from '../src/index.ts'
  * the official plugin repos ship (dsh-external/turtle-ui,
  * packages/ui/jsonrpc).
  */
-describe('dsh-better-sidebar plugin export shape', () => {
+describe('dsh-apes-sidebar plugin export shape', () => {
   it('has the namespace-plugin export shape (no stray default) so the Loader keeps name/inject/Config/apply', () => {
     expect('default' in sidebar).toBe(false)
     expect(typeof sidebar.apply).toBe('function')
@@ -16,7 +16,7 @@ describe('dsh-better-sidebar plugin export shape', () => {
     const loader = Object.create(Loader.prototype) as Loader
     const unwrapped = loader.unwrapExports(sidebar) as Record<string, unknown>
     expect(unwrapped).toBe(sidebar)
-    expect(unwrapped.name).toBe('dsh-better-sidebar')
+    expect(unwrapped.name).toBe('dsh-apes-sidebar')
     expect(unwrapped.inject).toEqual(['webServer', 'sessions', 'webRuntime', 'tools'])
     expect(unwrapped.Config).toBeDefined()
     expect(typeof unwrapped.apply).toBe('function')
@@ -53,7 +53,7 @@ describe('dsh-better-sidebar plugin export shape', () => {
 
   it('registers the side card preferences schema with the documented defaults', async () => {
     const { PrefsSchema, SIDEBAR_PREFS_NS, SIDEBAR_PREFS_DEFAULTS } = await import('../src/config.ts')
-    expect(SIDEBAR_PREFS_NS).toBe('dsh-better-sidebar')
+    expect(SIDEBAR_PREFS_NS).toBe('dsh-apes-sidebar')
     const resolved = (PrefsSchema as unknown as {
       (input: Record<string, unknown> | undefined): Record<string, unknown>
     })(undefined)