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)

hermes_cli/config.py

@@ -1881,6 +1881,24 @@ def _normalize_max_turns_config(config: Dict[str, Any]) -> Dict[str, Any]:
 
 
 
+def read_raw_config() -> Dict[str, Any]:
+    """Read ~/.hermes/config.yaml as-is, without merging defaults or migrating.
+
+    Returns the raw YAML dict, or ``{}`` if the file doesn't exist or can't
+    be parsed.  Use this for lightweight config reads where you just need a
+    single value and don't want the overhead of ``load_config()``'s deep-merge
+    + migration pipeline.
+    """
+    try:
+        config_path = get_config_path()
+        if config_path.exists():
+            with open(config_path, encoding="utf-8") as f:
+                return yaml.safe_load(f) or {}
+    except Exception:
+        pass
+    return {}
+
+
 def load_config() -> Dict[str, Any]:
     """Load configuration from ~/.hermes/config.yaml."""
     import copy