refactor: move search_usage to utils/searchusage, remove brave stub

- Rename agent/tools/search_usage.py → utils/searchusage.py
  (not an LLM tool, matches utils/ naming convention)
- Remove redundant _fetch_brave_usage — handled by else branch
- Move test to tests/utils/test_searchusage.py

Made-with: Cursor

nanobot/command/builtin.py

@@ -64,7 +64,7 @@ async def cmd_status(ctx: CommandContext) -> OutboundMessage:
     # Fetch web search provider usage (best-effort, never blocks the response)
     search_usage_text: str | None = None
     try:
-        from nanobot.agent.tools.search_usage import fetch_search_usage
+        from nanobot.utils.searchusage import fetch_search_usage
         web_cfg = getattr(getattr(loop, "config", None), "tools", None)
         web_cfg = getattr(web_cfg, "web", None) if web_cfg else None
         search_cfg = getattr(web_cfg, "search", None) if web_cfg else None

nanobot/utils/searchusage.py

@@ -81,10 +81,8 @@ async def fetch_search_usage(
 
     if p == "tavily":
         return await _fetch_tavily_usage(api_key)
-    elif p == "brave":
-        return await _fetch_brave_usage(api_key)
     else:
-        # duckduckgo, searxng, jina, unknown — no usage API
+        # brave, duckduckgo, searxng, jina, unknown — no usage API
         return SearchUsageInfo(provider=p, supported=False)
 
 
@@ -171,13 +169,3 @@ def _parse_tavily_usage(data: dict[str, Any]) -> SearchUsageInfo:
     )
 
 
-# ---------------------------------------------------------------------------
-# Brave
-# ---------------------------------------------------------------------------
-
-async def _fetch_brave_usage(api_key: str | None) -> SearchUsageInfo:
-    """
-    Brave Search does not have a public usage/quota endpoint.
-    Rate-limit headers are returned per-request, not queryable standalone.
-    """
-    return SearchUsageInfo(provider="brave", supported=False)

tests/utils/test_searchusage.py

@@ -5,7 +5,7 @@ from __future__ import annotations
 import pytest
 from unittest.mock import AsyncMock, MagicMock, patch
 
-from nanobot.agent.tools.search_usage import (
+from nanobot.utils.searchusage import (
     SearchUsageInfo,
     _parse_tavily_usage,
     fetch_search_usage,