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/examples/acp-demo/src/bin.ts

@@ -0,0 +1,35 @@
+#!/usr/bin/env node
+/**
+ * Boot an ACP stdio server from `cordis.yml`; usage is
+ * `dsh-acp-demo [--config path]`, defaulting to `./cordis.yml`. Shared env
+ * loading, Loader guards, snapshot config selection, and settled-tree boot live
+ * in dsh-app-boot. Replay skips `.env` and selects sibling
+ * `cordis.snapshot.yml` so a stray key cannot trigger a model call. EOF disposes
+ * and flushes snapshot runs; editors normally own process lifetime. Stdout is
+ * reserved for JSON-RPC, so diagnostics go only to stderr.
+ * @module @deepseek-ai/dsh-acp-demo/bin
+ */
+
+import { parseArgs } from 'node:util'
+import { boot, installFailLoud, loadEnv, resolveConfigPath } from '@deepseek-ai/dsh-app-boot'
+
+const NAME = 'dsh-acp-demo'
+
+/* v8 ignore start -- thin self-executing composition over the unit-tested
+   dsh-app-boot helpers; exercised end-to-end by the snapshot suite and the
+   built-bin smoke */
+installFailLoud(NAME)
+const snapshotMode = process.env['DSH_SNAPSHOT']
+if (snapshotMode !== 'replay') loadEnv(NAME)
+const { values } = parseArgs({
+  args: process.argv.slice(2),
+  options: { config: { type: 'string', short: 'c' } },
+  strict: true,
+})
+const ctx = await boot(NAME, resolveConfigPath(values.config ?? './cordis.yml', snapshotMode))
+if (snapshotMode !== undefined) {
+  process.stdin.on('end', () => {
+    void ctx.fiber.dispose().then(() => { process.exit(0) })
+  })
+}
+/* v8 ignore stop */