feat(hooks): add duration_ms to post_tool_call + transform_tool_result

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)

model_tools.py

@@ -24,6 +24,7 @@ import json
 import asyncio
 import logging
 import threading
+import time
 from typing import Dict, Any, List, Optional, Tuple
 
 from tools.registry import discover_builtin_tools, registry
@@ -563,6 +564,14 @@ def handle_function_call(
             except Exception:
                 pass  # file_tools may not be loaded yet
 
+        # Measure tool dispatch latency so post_tool_call and
+        # transform_tool_result hooks can observe per-tool duration.
+        # Inspired by Claude Code 2.1.119, which added ``duration_ms`` to
+        # PostToolUse hook inputs so plugin authors can build latency
+        # dashboards, budget alerts, and regression canaries without having
+        # to wrap every tool manually.  We use monotonic() so the value is
+        # unaffected by wall-clock adjustments during the call.
+        _dispatch_start = time.monotonic()
         if function_name == "execute_code":
             # Prefer the caller-provided list so subagents can't overwrite
             # the parent's tool set via the process-global.
@@ -578,6 +587,7 @@ def handle_function_call(
                 task_id=task_id,
                 user_task=user_task,
             )
+        duration_ms = int((time.monotonic() - _dispatch_start) * 1000)
 
         try:
             from hermes_cli.plugins import invoke_hook
@@ -589,6 +599,7 @@ def handle_function_call(
                 task_id=task_id or "",
                 session_id=session_id or "",
                 tool_call_id=tool_call_id or "",
+                duration_ms=duration_ms,
             )
         except Exception:
             pass
@@ -609,6 +620,7 @@ def handle_function_call(
                 task_id=task_id or "",
                 session_id=session_id or "",
                 tool_call_id=tool_call_id or "",
+                duration_ms=duration_ms,
             )
             for hook_result in hook_results:
                 if isinstance(hook_result, str):