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/tests/snapshots/bash-tool/result.expected.json

@@ -0,0 +1 @@
+{"status":"ok","reason":{"kind":"completed"},"finalResponse":"dsh-sdk-proof-7391"}