ci: add check-sensitive pre-merge gate

Hand-written change from the internal SDK repository. The original commit
message is intentionally not mirrored; see the source repository for details.

Sync-Source-Commit: 6d8c52ddd4cc0b35551c8d58d392ffca5b91cdce
Hand-Written-Reason: No Ark-APIs provenance marker; treated as a hand-written source commit.
Release-Version: 0.7.0

Author: ark-hand[bot]

examples/self_hosted_mcp_worker/README.md

@@ -1,6 +1,6 @@
 # Self-hosted MCP worker
 
-This example follows Anthropic's client-side MCP helper example at the same
+This example follows the client-side MCP helper pattern at the same
 level of abstraction: connect to an MCP server, discover its tools, convert
 them, and run an existing self-hosted Environment Worker.
 

src/arkruntime/_managed_agents_serialize.py

@@ -26,7 +26,7 @@ def _dump(value: Any) -> Any:
     - `NOT_GIVEN` → dropped by the caller (returned as-is; caller filters).
     - `pydantic.BaseModel` → `.model_dump(exclude_unset=True, by_alias=True)`
       so unset Optional fields don't leak `null` onto the wire (server-side
-      is Anthropic-flavoured `omit == null == unset`).
+      uses the `omit == null == unset` convention).
     - `enum.Enum` → its `.value`. Handles enum-typed fields (e.g.
       `EnvConfigType.CLOUD` → `"cloud"`) that get passed positionally.
     - `list` / `tuple` → element-wise recursion.