refactor: add tool_error/tool_result helpers + read_raw_config, migrate 129 callsites

Add three reusable helpers to eliminate pervasive boilerplate:

tools/registry.py — tool_error() and tool_result():
  Every tool handler returns JSON strings. The pattern
  json.dumps({"error": msg}, ensure_ascii=False) appeared 106 times,
  and json.dumps({"success": False, "error": msg}, ...) another 23.
  Now: tool_error(msg) or tool_error(msg, success=False).

  tool_result() handles arbitrary result dicts:
  tool_result(success=True, data=payload) or tool_result(some_dict).

hermes_cli/config.py — read_raw_config():
  Lightweight YAML reader that returns the raw config dict without
  load_config()'s deep-merge + migration overhead. Available for
  callsites that just need a single config value.

Migration (129 callsites across 32 files):
- tools/: browser_camofox (18), file_tools (10), homeassistant (8),
  web_tools (7), skill_manager (7), cronjob (11), code_execution (4),
  delegate (5), send_message (4), tts (4), memory (7), session_search (3),
  mcp (2), clarify (2), skills_tool (3), todo (1), vision (1),
  browser (1), process_registry (2), image_gen (1)
- plugins/memory/: honcho (9), supermemory (9), hindsight (8),
  holographic (7), openviking (7), mem0 (7), byterover (6), retaindb (2)
- agent/: memory_manager (2), builtin_memory_provider (1)

tools/browser_tool.py

@@ -1618,7 +1618,7 @@ def _camofox_eval(expression: str, task_id: Optional[str] = None) -> str:
                 "error": "JavaScript evaluation is not supported by this Camofox server. "
                          "Use browser_snapshot or browser_vision to inspect page state.",
             })
-        return json.dumps({"success": False, "error": error_msg})
+        return tool_error(error_msg, success=False)
 
 
 def _maybe_start_recording(task_id: str):
@@ -2102,7 +2102,7 @@ if __name__ == "__main__":
 # ---------------------------------------------------------------------------
 # Registry
 # ---------------------------------------------------------------------------
-from tools.registry import registry
+from tools.registry import registry, tool_error
 
 _BROWSER_SCHEMA_MAP = {s["name"]: s for s in BROWSER_TOOL_SCHEMAS}