fix: address review — python smoke caller, contract prose, fixture header hygiene

ds-review-bot findings: the packaged Python runtime smoke's scripted
run_code call gains the required description; the ToolDefinition JSDoc
and the Code Mode foundation note (both languages, pair re-recorded) now
state both required parameters; the cordis-dynamic-toolchain fixture's
request/header line is re-compacted so the header-scrub hygiene guard
passes (my earlier patch had re-spaced it). The TUI terminal fixture was
already regenerated from keyless replay in the previous commit.

packages/core/tools/src/code-mode.ts

@@ -170,8 +170,9 @@ function renderValue(value: JsonValue): string {
 type RunCodeOutput = { logs: string[]; result?: JsonValue }
 
 /**
- * Build the `run_code` {@link ToolDefinition}: one required `code` parameter,
- * executed through the dispatch bridge described above. The
+ * Build the `run_code` {@link ToolDefinition}: required `code` and
+ * `description` parameters, executed through the dispatch bridge described
+ * above. The
  * registry reserves it as presentation infrastructure under non-native modes,
  * outside the filterable global/scoped capability layers.
  * @param registry - the owning registry (sub-calls go through its `execute`,