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)

plugins/memory/holographic/__init__.py

@@ -23,6 +23,7 @@ import re
 from typing import Any, Dict, List
 
 from agent.memory_provider import MemoryProvider
+from tools.registry import tool_error
 from .store import MemoryStore
 from .retrieval import FactRetriever
 
@@ -230,7 +231,7 @@ class HolographicMemoryProvider(MemoryProvider):
             return self._handle_fact_store(args)
         elif tool_name == "fact_feedback":
             return self._handle_fact_feedback(args)
-        return json.dumps({"error": f"Unknown tool: {tool_name}"})
+        return tool_error(f"Unknown tool: {tool_name}")
 
     def on_session_end(self, messages: List[Dict[str, Any]]) -> None:
         if not self._config.get("auto_extract", False):
@@ -296,7 +297,7 @@ class HolographicMemoryProvider(MemoryProvider):
             elif action == "reason":
                 entities = args.get("entities", [])
                 if not entities:
-                    return json.dumps({"error": "reason requires 'entities' list"})
+                    return tool_error("reason requires 'entities' list")
                 results = retriever.reason(
                     entities,
                     category=args.get("category"),
@@ -334,12 +335,12 @@ class HolographicMemoryProvider(MemoryProvider):
                 return json.dumps({"facts": facts, "count": len(facts)})
 
             else:
-                return json.dumps({"error": f"Unknown action: {action}"})
+                return tool_error(f"Unknown action: {action}")
 
         except KeyError as exc:
-            return json.dumps({"error": f"Missing required argument: {exc}"})
+            return tool_error(f"Missing required argument: {exc}")
         except Exception as exc:
-            return json.dumps({"error": str(exc)})
+            return tool_error(str(exc))
 
     def _handle_fact_feedback(self, args: dict) -> str:
         try:
@@ -348,9 +349,9 @@ class HolographicMemoryProvider(MemoryProvider):
             result = self._store.record_feedback(fact_id, helpful=helpful)
             return json.dumps(result)
         except KeyError as exc:
-            return json.dumps({"error": f"Missing required argument: {exc}"})
+            return tool_error(f"Missing required argument: {exc}")
         except Exception as exc:
-            return json.dumps({"error": str(exc)})
+            return tool_error(str(exc))
 
     # -- Auto-extraction (on_session_end) ------------------------------------