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/context/time-context/README.md

@@ -1,6 +1,6 @@
 # @deepseek-ai/dsh-time-context
 
-Opt-in dynamic system-prompt context with the current zoned time and elapsed time since the latest model-visible message before the turn. `dsh-agent-core` and shipped examples do not mount it. Decision record: [the time-context RFC](../../../docs/rfc/implemented/feature/2026-07-14-time-context-plugin.md).
+Opt-in dynamic system-prompt context with the current zoned time and elapsed time since the latest model-visible message before the turn. `dsh-agent-spine-demo` and shipped examples do not mount it. Decision record: [the time-context RFC](../../../docs/rfc/implemented/feature/2026-07-14-time-context-plugin.md).
 
 ## Config
 

packages/context/time-context/tests/fixtures/cordis.yml

@@ -9,7 +9,7 @@
   name: '@deepseek-ai/dsh-time-context'
 
 - id: stdio-agent
-  name: '@deepseek-ai/dsh-stdio-agent'
+  name: '@deepseek-ai/dsh-stdio-demo'
   config:
     model: mock-echo
     persona: 'Test the time-context plugin.'

packages/context/time-context/tests/time-context.e2e.ts

@@ -6,7 +6,7 @@ import { fileURLToPath } from 'node:url'
 import { afterEach, describe, expect, it } from 'vitest'
 import { foldRequestHeader, type SessionEvent } from '@deepseek-ai/dsh-session'
 
-const binScript = fileURLToPath(new URL('../../../ui/stdio-agent/src/bin.ts', import.meta.url))
+const binScript = fileURLToPath(new URL('../../../examples/stdio-demo/src/bin.ts', import.meta.url))
 const configPath = fileURLToPath(new URL('./fixtures/cordis.yml', import.meta.url))
 const repoTsconfig = fileURLToPath(new URL('../../../../tsconfig.json', import.meta.url))
 const tsxLoader = fileURLToPath(import.meta.resolve('tsx'))