feat(tools): live dispatch lifecycle + native-contract parallel sub-calls in Code Mode

The bridge replaces its serialization queue with a pool that reuses the
native concurrency contract: submissions classify through
registry.executionMode (fail-closed isConcurrencySafe), start strictly in
submission order, overlap up to the validated maxParallelSubCalls config
(default 10; 1 restores serial), and exclusive calls drain the pool, run
alone, and bar later calls. Each started sub-call logs a
tool/code-dispatch-start event at pool entry; the existing
tool/code-dispatch settles the pair (started ⇔ settles exactly once;
abandoned queued calls log neither). SDK prompt guidance now states the
true Promise.all contract — re-recorded across every code/both-mode
snapshot (plus the stale cordis-dynamic-toolchain fixture gaining the
required description arg).

Client: CodeSubCall widens to RunningToolCall | ToolResultNode — starts
land the running shape (rows wear the native running ring), settles
replace in place preserving start order, callTime pairs to the start
time. Fixture emits start/settle pairs; jsdom pins the running sub-row;
runtime specs pin in-place settlement and out-of-order completion.

packages/client/runtime/src/client/sessions/conversation.ts

@@ -128,15 +128,19 @@ export type ConversationNode =
   | UnknownSurfaceNode
 
 /**
- * One `run_code` sub-dispatch materialized as a {@link ToolResultNode} so every
- * consumer (tool rows, details panel) renders it through the exact components
- * that render a native settled call. Never part of the surface `nodes` flow —
- * sub-calls live under their parent via {@link ConversationSnapshot.codeDispatches}.
- * `callId` is the deterministic sub-call id (`<parent>:code:<n>`); `call`
- * carries the sub-tool name and its JSON-stringified logged arguments;
- * `content`/`isError` are the sub-call's complete logged outcome.
+ * One `run_code` sub-dispatch materialized in the native call-block shapes so
+ * every consumer (tool rows, details panel) renders it through the exact
+ * components that render a native call: a started-but-unsettled sub-call is a
+ * {@link RunningToolCall} (rows derive the running state from the shape,
+ * exactly as for native calls) and its `tool/code-dispatch` settlement
+ * replaces it in place with the {@link ToolResultNode} form. Never part of
+ * the surface `nodes` flow — sub-calls live under their parent via
+ * {@link ConversationSnapshot.codeDispatches}. `callId` is the deterministic
+ * sub-call id (`<parent>:code:<n>`); the call side carries the sub-tool name
+ * and its JSON-stringified logged arguments; `content`/`isError` are the
+ * settled sub-call's complete logged outcome.
  */
-export type CodeSubCall = ToolResultNode
+export type CodeSubCall = RunningToolCall | ToolResultNode
 
 /** In-flight tool card material: tool/call seen, tool/result not yet. */
 export interface RunningToolCall {