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/ui/jsonrpc/tests/plugin-apply.spec.ts

@@ -6,7 +6,7 @@ import { tmpdir } from 'node:os'
 import { PassThrough, Writable } from 'node:stream'
 import { afterEach, describe, expect, it, vi } from 'vitest'
 import { Context } from 'cordis'
-import * as agentCore from '@deepseek-ai/dsh-agent-core'
+import * as agentCore from '@deepseek-ai/dsh-agent-spine-demo'
 import SessionPersistenceJsonl from '@deepseek-ai/dsh-session-persistence-jsonl'
 import * as jsonrpc from '../src/index.ts'
 

packages/ui/jsonrpc/tests/server.spec.ts

@@ -7,7 +7,7 @@ import { afterEach, describe, expect, it, vi } from 'vitest'
 import { Context } from 'cordis'
 import { AgentId, type Agent, type AgentHandle } from '@deepseek-ai/dsh-agent'
 import { SessionId } from '@deepseek-ai/dsh-session'
-import * as agentCore from '@deepseek-ai/dsh-agent-core'
+import * as agentCore from '@deepseek-ai/dsh-agent-spine-demo'
 import SessionPersistenceJsonl from '@deepseek-ai/dsh-session-persistence-jsonl'
 import * as LlmDeepSeek from '@deepseek-ai/dsh-llm-deepseek'
 import SubagentService, { type SubagentRunEndInfo } from '@deepseek-ai/dsh-subagent'