feat(tool-subagent): default maxDepth 1 with at-cap schema hiding

An omitted maxDepth meant unbounded recursion, and the shipped examples
shipped that default. maxDepth now defaults to 1; a numeric cap requires
the provider's depthLimit capability (the mount fails loud and points to
the explicit 'provider-managed' opt-out for out-of-process providers),
and a child AT the cap loses the delegating tool from its own schema via
the child toolFilter — prompt-face hiding on top of the execution-face
depth check. Examples pin maxDepth explicitly. The ACP snapshot harness
gains Scenario.childToolOmissions so a child session may legitimately
omit declared delegation tools from its pinned header and prompt;
affected subagent/workflow goldens are re-recorded.

scripts/gen-tool-catalog.ts

@@ -39,11 +39,16 @@ import * as ToolWorkflow from '@deepseek-ai/dsh-tool-workflow'
 const root = resolve(import.meta.dirname, '..')
 const OUT = 'docs/tool-catalog.md'
 
-/** Register the descriptor needed to mount schema-producing consumers. */
+/**
+ * Register the descriptor needed to mount schema-producing consumers. Declares
+ * the full capability set of the shipped in-process providers so consumers
+ * mount under their shipped defaults (tool-subagent's default numeric maxDepth
+ * requires `depthLimit`).
+ */
 function registerCatalogSubagentProvider(ctx: Context, name: string): void {
   const provider: SubagentProvider = {
     name,
-    capabilities: { outputSchema: false, depthLimit: false, toolFilter: false, persona: false },
+    capabilities: { outputSchema: true, depthLimit: true, toolFilter: true, persona: true },
     inheritsParentContext: false,
     start: () => Promise.reject(new Error('tool-catalog provider cannot start a child')),
   }