style: fix linting and formatting issues

- Run black formatter on all Python files
- Fix ruff linting issues:
  - Remove unused imports
  - Remove unused variables
  - Fix f-string without placeholders
- All 37 tests still pass
- Code quality improved for CI/CD compliance

🧹 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

config.py

@@ -9,7 +9,9 @@ __author__ = "Fahad Gilani"
 
 # Model configuration
 DEFAULT_MODEL = "gemini-2.5-pro-preview-06-05"
-THINKING_MODEL = "gemini-2.0-flash-thinking-exp"  # Enhanced reasoning model for think_deeper
+THINKING_MODEL = (
+    "gemini-2.0-flash-thinking-exp"  # Enhanced reasoning model for think_deeper
+)
 MAX_CONTEXT_TOKENS = 1_000_000  # 1M tokens for Gemini Pro
 
 # Temperature defaults for different tool types