test(pkg): snapshot advanced Python SDK executable flow

The existing assertion-only executable smoke proved selected outputs but could not detect drift across the integrated Python SDK, JSON-RPC notification stream, and persisted session shape.

Keep this separate from ACP snapshots because it must launch the actual platform-native packaged executable through the Python SDK. The deterministic model drives Cordis dynamic tool mounting, a Code Mode worker dispatch, direct spawn delegation, workflow-worker delegation, plugin disposal, and the parent/child persistence lineage.

Commit four portable goldens for the SDK result and three JSONL logs. Normalize timestamps, temporary paths, opaque session and agent identifiers, and bulky request headers while retaining ordering, tool names and arguments, header deltas, results, lineage, and final responses so all native build legs compare the same behavior.

Run the comparison in the label-gated executable build workflow and document the current coverage in the paired implemented RFC.

docs/rfc/implemented/architecture/2026-07-10-single-file-executable-sdk-runtime-distribution.md

@@ -62,7 +62,7 @@ The exe's "must be explicitly configured" hard semantic is unchanged; the zero-c
 
 ## Testing
 
-The verification surface has three tiers. Mechanism tier: the measured conclusions for the `--sea` chain are embedded in the Decision sections (ESM dynamic import inside the VFS, single cordis instance, fail-loud config chain, `node:sqlite`, macOS ad-hoc signing runs). SDK tier: the complete keyless pytest suite covers the client protocol against a fake runtime peer, subprocess cleanup, absolute cwd propagation, dual-carrier launch, and carrier resolution; root CI runs it on Python 3.10. End-to-end tier: every platform build completes a turn against a mock endpoint through the default SDK path, a custom config, and the direct binary protocol, with final text and JSONL checked. The custom config additionally drives `run_code` and a zero-agent `workflow` through their real worker files inside the packaged VFS. Its platform wheel is then installed in a clean venv and run without `runtime_bin`. The JSON-RPC protocol is not part of the ACP snapshot system, so there is no snapshot tier (an explicitly named gap, not an oversight).
+The verification surface has three tiers. Mechanism tier: the measured conclusions for the `--sea` chain are embedded in the Decision sections (ESM dynamic import inside the VFS, single cordis instance, fail-loud config chain, `node:sqlite`, macOS ad-hoc signing runs). SDK tier: the complete keyless pytest suite covers the client protocol against a fake runtime peer, subprocess cleanup, absolute cwd propagation, dual-carrier launch, and carrier resolution; root CI runs it on Python 3.10. End-to-end tier: every platform build completes a turn against a mock endpoint through the default SDK path, a custom config, and the direct binary protocol, with final text and JSONL checked. The custom config additionally drives `run_code` and a zero-agent `workflow` through their real worker files inside the packaged VFS. The same build leg runs a committed executable-specific snapshot through the Python SDK: a keyless scripted model mounts a Cordis plugin that registers a tool, invokes that tool from `run_code`, runs a direct spawn subagent and a workflow that starts a second spawn child, then unmounts the plugin. The comparison normalizes the SDK result and notification stream plus the parent and two child JSONL logs. This harness stays separate from ACP's `pnpm run test:snapshot` because the protocols and build artifacts differ. The platform wheel is then installed in a clean venv and run without `runtime_bin`.
 
 Manual-driving caveat: the bin treats stdin EOF as "the client is gone" and disposes immediately, so a short-lived pipe aborts an in-flight turn — pipe-driven runs must keep stdin open until the turn ends.