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/tts_tool.py

@@ -466,7 +466,7 @@ def text_to_speech_tool(
         str: JSON result with success, file_path, and optionally MEDIA tag.
     """
     if not text or not text.strip():
-        return json.dumps({"success": False, "error": "Text is required"}, ensure_ascii=False)
+        return tool_error("Text is required", success=False)
 
     # Truncate very long text with a warning
     if len(text) > MAX_TEXT_LENGTH:
@@ -607,17 +607,17 @@ def text_to_speech_tool(
         # Configuration errors (missing API keys, etc.)
         error_msg = f"TTS configuration error ({provider}): {e}"
         logger.error("%s", error_msg)
-        return json.dumps({"success": False, "error": error_msg}, ensure_ascii=False)
+        return tool_error(error_msg, success=False)
     except FileNotFoundError as e:
         # Missing dependencies or files
         error_msg = f"TTS dependency missing ({provider}): {e}"
         logger.error("%s", error_msg, exc_info=True)
-        return json.dumps({"success": False, "error": error_msg}, ensure_ascii=False)
+        return tool_error(error_msg, success=False)
     except Exception as e:
         # Unexpected errors
         error_msg = f"TTS generation failed ({provider}): {e}"
         logger.error("%s", error_msg, exc_info=True)
-        return json.dumps({"success": False, "error": error_msg}, ensure_ascii=False)
+        return tool_error(error_msg, success=False)
 
 
 # ===========================================================================
@@ -950,7 +950,7 @@ if __name__ == "__main__":
 # ---------------------------------------------------------------------------
 # Registry
 # ---------------------------------------------------------------------------
-from tools.registry import registry
+from tools.registry import registry, tool_error
 
 TTS_SCHEMA = {
     "name": "text_to_speech",