Fix UnboundLocalError in training thread exception handlers

[Copilot]

Problem

Training threads were failing with two related errors:

1. 'DQNAgent' object has no attribute 'train_step'
2. UnboundLocalError: cannot access local variable 'traceback' where it is not associated with a value

The root cause was redundant local import traceback statements inside exception handlers in the background_train and train_step methods.

Root Cause Analysis

The issue occurred in two locations in aimodel.py:

# Line 693-696 (background_train method)
except Exception as e:
    print(f"Training error in {worker_id}: {e}")
    import traceback  # ← Problematic local import
    traceback.print_exc()

# Line 913-916 (train_step method)  
except Exception as e:
    print(f"Training error: {e}")
    import traceback  # ← Problematic local import
    traceback.print_exc()

The module already imports traceback at the top level (line 66), making these local imports redundant and potentially problematic in threading contexts where the local import can cause variable scoping issues.

Solution

Removed the redundant local import traceback statements and use the existing module-level import:

# Fixed version
except Exception as e:
    print(f"Training error in {worker_id}: {e}")
    traceback.print_exc()  # Uses module-level import

Testing

• ✅ Verified train_step method exists and is callable
• ✅ Tested training threads run without AttributeError or UnboundLocalError
• ✅ Confirmed main application runs normally without errors
• ✅ All training worker threads start and execute successfully

The training system now operates correctly with proper exception handling and no thread-related import issues.

Created from VS Code via the GitHub Pull Request extension.

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