fix(backend): address coderabbitai nitpicks in cost tracking files

- token_tracking.py: convert logger.info %s calls to f-strings per style guide
- cost_tracking.py: simplify metadata=meta (was redundantly `meta or None`);
  move token_tracking imports to module level to remove # noqa: PLC0415 suppressors
- baseline/service.py: remove dead UnboundLocalError from except tuple since
  response is initialized to None before the try block

autogpt_platform/backend/backend/copilot/baseline/service.py

@@ -445,7 +445,7 @@ async def _baseline_llm_caller(
                     cost = float(cost_header)
                     if math.isfinite(cost):
                         state.cost_usd = (state.cost_usd or 0.0) + max(0.0, cost)
-        except (ValueError, AttributeError, UnboundLocalError):
+        except (ValueError, AttributeError):
             pass
 
         # Always persist partial text so the session history stays consistent,

autogpt_platform/backend/backend/copilot/token_tracking.py

@@ -144,23 +144,14 @@ async def persist_and_record_usage(
 
     if cache_read_tokens or cache_creation_tokens:
         logger.info(
-            "%s Turn usage: uncached=%d, cache_read=%d, cache_create=%d,"
-            " output=%d, total=%d, cost_usd=%s",
-            log_prefix,
-            prompt_tokens,
-            cache_read_tokens,
-            cache_creation_tokens,
-            completion_tokens,
-            total_tokens,
-            cost_usd,
+            f"{log_prefix} Turn usage: uncached={prompt_tokens}, cache_read={cache_read_tokens},"
+            f" cache_create={cache_creation_tokens}, output={completion_tokens},"
+            f" total={total_tokens}, cost_usd={cost_usd}"
         )
     else:
         logger.info(
-            "%s Turn usage: prompt=%d, completion=%d, total=%d",
-            log_prefix,
-            prompt_tokens,
-            completion_tokens,
-            total_tokens,
+            f"{log_prefix} Turn usage: prompt={prompt_tokens}, completion={completion_tokens},"
+            f" total={total_tokens}"
         )
 
     if user_id:

autogpt_platform/backend/backend/executor/cost_tracking.py

@@ -6,6 +6,10 @@ import threading
 from typing import TYPE_CHECKING, Any, cast
 
 from backend.blocks._base import Block, BlockSchema
+from backend.copilot.token_tracking import _pending_log_tasks as _copilot_tasks
+from backend.copilot.token_tracking import (
+    _pending_log_tasks_lock as _copilot_tasks_lock,
+)
 from backend.data.execution import NodeExecutionEntry
 from backend.data.model import NodeExecutionStats
 from backend.data.platform_cost import PlatformCostEntry, usd_to_microdollars
@@ -83,13 +87,6 @@ async def drain_pending_cost_logs(timeout: float = 5.0) -> None:
                 timeout,
             )
     # Also drain copilot cost log tasks (token_tracking._pending_log_tasks)
-    from backend.copilot.token_tracking import (  # noqa: PLC0415
-        _pending_log_tasks as _copilot_tasks,
-    )
-    from backend.copilot.token_tracking import (  # noqa: PLC0415
-        _pending_log_tasks_lock as _copilot_tasks_lock,
-    )
-
     with _copilot_tasks_lock:
         copilot_pending = [t for t in _copilot_tasks if t.get_loop() is current_loop]
     if copilot_pending:
@@ -286,7 +283,7 @@ async def log_system_credential_cost(
                     model=model_name,
                     tracking_type=tracking_type,
                     tracking_amount=tracking_amount,
-                    metadata=meta or None,
+                    metadata=meta,
                 ),
             )
             return  # One log per execution is enough