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.

python/sdk-runtime/src/deepseek_harness_runtime/__init__.py

@@ -8,7 +8,7 @@ Two runtime carriers coexist under ``runtime/``, both injected by the repo's
   {x64, arm64}); the target machine needs no Node installation.
 - **node (dev-only)**: the full deploy closure under ``runtime/node/``
   (``package.json`` + ``node_modules/``), executed as ``node
-  runtime/node/node_modules/@deepseek-ai/dsh-jsonrpc-agent/lib/bin.js`` on a
+  runtime/node/node_modules/@deepseek-ai/dsh-jsonrpc-demo/lib/bin.js`` on a
   system Node >= 22.19. It is the current checkout's source build, never
   selected automatically, and excluded from wheel/sdist distributions.
 

python/sdk-runtime/src/deepseek_harness_runtime/runtime/cordis.yml

@@ -8,7 +8,7 @@
 
 # Agent spine; the SDK server creates agents per sessionId.
 - id: agent-core
-  name: '@deepseek-ai/dsh-agent-core'
+  name: '@deepseek-ai/dsh-agent-spine-demo'
 
 # Stock DeepSeek adapters. Loading requires an API key; initialize and shutdown
 # may use a dummy key because they do not call the model.