test(sdk): snapshot suite over the SDK path; docs for the SDK stack

- examples/jsonrpc-agent gains its first snapshot suite (sdk.snapshot.ts):
  the real dsh-jsonrpc-agent runtime driven through the real dsh-sdk-client,
  keyless llm-replay behind a new cordis.snapshot.yml overlay; three recorded
  scenarios (text turn, bash tool, spawn subagent) pin the notification
  stream, the SDK turn result, and the persisted parent+child session logs.
- Bilingual READMEs for dsh-sdk-protocol / dsh-sdk-client / dsh-subagent-sdk;
  sdk/ and subagent/ group tables extended; dsh-jsonrpc README points at the
  extracted protocol package; Agent Note (en+zh) owns the decision.
- The proposed make-jsonrpc-directional note is updated for the transport's
  new home and its second (client) consumer.
- Model Experience sentence allowlist entries for the two client-side
  packages; module graph + config catalog regenerated; i18n pairings
  recorded. doc-sync passes 24/24.

examples/jsonrpc-agent/cordis.snapshot.yml

@@ -0,0 +1,28 @@
+# Keyless replay includes the live `cordis.yml`, disables the key-requiring
+# DeepSeek adapter, and inserts `llm-replay` to serve recorded JSONL without a
+# key or network; every other entry remains shared. The replay provider
+# catalog claims the `deepseek` provider so the SDK server's `initialize`
+# finds it owned and never mounts the real-adapter fallback. The SDK snapshot
+# suite passes this path explicitly through `DSH_CORDIS_CONFIG` (the
+# jsonrpc-demo bin performs no DSH_SNAPSHOT config swap of its own), and
+# `llm-replay` reads `DSH_SNAPSHOT_FILE` / `DSH_SNAPSHOT_CHILD_FILES` from the
+# harness. Stdout remains reserved for JSON-RPC frames.
+- id: base
+  name: '@cordisjs/plugin-include'
+  config:
+    path: ./cordis.yml
+    patches:
+      # `name` asserts the target: a mismatch skips the patch and warns only
+      # when a logger exists.
+      - id: llm-deepseek
+        name: '@deepseek-ai/dsh-llm-deepseek'
+        disabled: true
+      - insert:
+          - id: llm-replay
+            name: '@deepseek-ai/dsh-llm-replay'
+            config:
+              providers:
+                - id: deepseek
+                  name: DeepSeek
+                  models:
+                    - id: deepseek-v4-flash