refactor: relocate demo app bundles to packages/examples/*-demo

Move the agent-spine bundle and the stdio/ACP/JSON-RPC app packages out of
core/ and ui/ into a new packages/examples/ group, renamed with a -demo
suffix so the npm name marks them as non-product surface:

  core/agent-core   -> examples/agent-spine-demo  (dsh-agent-spine-demo)
  ui/stdio-agent    -> examples/stdio-demo        (dsh-stdio-demo)
  ui/acp-agent      -> examples/acp-demo          (dsh-acp-demo)
  ui/jsonrpc-agent  -> examples/jsonrpc-demo      (dsh-jsonrpc-demo)

Update every code/config/test reference and reference-only doc mentions, and
regenerate module-graph, config-catalog, and doc-graphs. The jsonrpc bin
(dsh-jsonrpc-agent) and single-file exe (dsh-jsonrpc-agent-pkg) keep their
names; the SDK runtime-startup surface is reconciled separately.

packages/subagent/subagent-acp/README.md

@@ -33,7 +33,7 @@ ACP advertises no start-time capabilities because this process cannot enforce th
   config:
     providerName: acp
     command: node
-    args: ['--import', 'tsx', './packages/ui/acp-agent/src/bin.ts', '--config', './examples/acp-agent/cordis.yml']
+    args: ['--import', 'tsx', './packages/examples/acp-demo/src/bin.ts', '--config', './examples/acp-agent/cordis.yml']
     permission: reject
     env:
       DEEPSEEK_API_KEY: !!js process.env.DEEPSEEK_API_KEY

packages/subagent/subagent-acp/tests/subagent-acp.e2e.ts

@@ -15,7 +15,7 @@ import * as acp from '../src/index.ts'
  */
 
 // The real acp-agent example: its bin + cordis.yml (the live DeepSeek config).
-const binScript = fileURLToPath(new URL('../../../ui/acp-agent/src/bin.ts', import.meta.url))
+const binScript = fileURLToPath(new URL('../../../examples/acp-demo/src/bin.ts', import.meta.url))
 const exampleConfig = fileURLToPath(new URL('../../../../examples/acp-agent/cordis.yml', import.meta.url))
 const tsxLoader = fileURLToPath(import.meta.resolve('tsx'))
 const repoTsconfig = fileURLToPath(new URL('../../../../tsconfig.json', import.meta.url))