feat(tools): run well-formed first calls to deferred tools

[Hmbown]

No-Issue: 0.10.1 release-readiness recovery and first-call tool work, found in dogfooding; no public issue tracks it.

Deferred tools kept every unused schema out of the pinned prefix, but a
deferred tool's first call never ran: it returned the schema and told
the model to retry, so ordinary investigation (list_dir, grep_files,
Web fetch, Run) spent a turn plus a tool-surface re-pin before doing
anything. Children and Workflow leaves also started with none of the
tools their assignment named explicitly.

• Parent and child: a first call that already matches the unseen schema
  (object, every required field, no undeclared field) executes and
  activates at the catalog tail. Malformed calls still get the schema.
  Hydration runs after every authority gate (deny/allow lists, Plan,
  repo law, approval), and dispatch still requires a registry spec, so
  this changes turn cost, not authority. The executed path emits a
  tool.deferred_first_use_executed audit record.
• Children warm their explicit allowed_tools onto the first request
  through the existing bounded activation cache (8 names / 16 KiB).
  Visibility only: grants, role posture and envelopes are unchanged.

Known limitation: argument types are left to each tool's own validation.

Evidence: 60 passed, 0 failed (13,192 skipped) across deferred,
small_surface, tool_catalog, hydrat and tool_search selections,
including a Scout whose well-formed first list_dir runs, whose
malformed call gets the schema, and whose write/edit stay refused. Two
tests that encoded the old never-execute behavior now use malformed
input to keep covering the schema-hint path. TUI all-target/all-feature
Clippy with CI flags and fmt passed.

🤖 Generated with Claude Code

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