fix: register the examples/ group in the tsconfig paths map

The @deepseek-ai/dsh-* wildcard maps each package name to its group's
src; the new packages/examples/ group needs its own glob, or the four
moved packages fall back to unbuilt lib/ and vitest cannot resolve them.
Also update the moved specs' plugin export-name assertions (acp-agent ->
acp-demo, stdio-agent -> stdio-demo, agent-core -> agent-spine-demo).

packages/examples/acp-demo/tests/acp-agent.spec.ts

@@ -113,7 +113,7 @@ describe('dsh-acp-demo composition', () => {
   })
 
   it('exposes its plugin shape', () => {
-    expect(acpAgent.name).toBe('acp-agent')
+    expect(acpAgent.name).toBe('acp-demo')
     expect(acpAgent.Config).toBeDefined()
   })
 
@@ -147,7 +147,7 @@ describe('dsh-acp-demo composition', () => {
     const loader = Object.create(Loader.prototype) as Loader
     const unwrapped = loader.unwrapExports(acpAgent) as Record<string, unknown>
     expect(unwrapped).toBe(acpAgent)
-    expect(unwrapped.name).toBe('acp-agent')
+    expect(unwrapped.name).toBe('acp-demo')
     expect(unwrapped.Config).toBeDefined()
     expect(typeof unwrapped.apply).toBe('function')
   })