feat(hooks): add duration_ms to post_tool_call + transform_tool_result (#15429)

Plugin hooks fired after a tool dispatch now receive an integer
duration_ms kwarg measuring how long the tool's registry.dispatch()
call took (time.monotonic() before/after). Inspired by Claude Code
2.1.119 which added the same field to PostToolUse hook inputs.

Wire points:
- model_tools.py: measure dispatch latency, pass duration_ms to
  invoke_hook("post_tool_call", ...) and invoke_hook("transform_tool_result", ...)
- hermes_cli/hooks.py: include duration_ms in the synthetic payload
  used by 'hermes hooks test' and 'hermes hooks doctor' so shell-hook
  authors see the same shape at development time as runtime
- shell hooks (agent/shell_hooks.py): no code change needed;
  _serialize_payload already surfaces non-top-level kwargs under
  payload['extra'], so duration_ms lands at extra.duration_ms for
  shell-hook scripts

Plugin authors can now build latency dashboards, per-tool SLO alerts,
and regression canaries without having to wrap every tool manually.

Test: tests/test_model_tools.py::test_post_tool_call_receives_non_negative_integer_duration_ms
E2E: real PluginManager + dispatch monkey-patched with a 50ms sleep,
hook callback observes duration_ms=50 (int).

Refs: https://code.claude.com/docs/en/changelog (2.1.119, Apr 23 2026)

hermes_cli/hooks.py

@@ -125,6 +125,7 @@ _DEFAULT_PAYLOADS = {
         "task_id": "test-task",
         "tool_call_id": "test-call",
         "result": '{"output": "hello"}',
+        "duration_ms": 42,
     },
     "pre_llm_call": {
         "session_id": "test-session",