Refactor code for improved readability and consistency

- Cleaned up whitespace and formatting in various files including http.py, language.py, logger.py, safe_exec.py, and SQL migration scripts.
- Consolidated import statements and removed unnecessary blank lines.
- Updated logging configuration for better clarity.
- Enhanced the safe execution code with improved error handling and logging.
- Removed commented-out code and unnecessary variables in backfill_zero_trades.py and other scripts.
- Added a pyproject.toml for Ruff and Vulture configuration.
- Introduced requirements-dev.txt for development dependencies.
- Removed commented-out stock entries in init.sql for cleaner migration scripts.

backend_api_python/app/data_sources/__init__.py

@@ -7,38 +7,26 @@ Improved version (refer to daily_stock_analysis project):
 - Data cache (cache_manager)
 - Anti-ban strategy (rate_limiter)
 """
+
+from app.data_sources.cache_manager import DataCache, get_kline_cache, get_realtime_cache, get_stock_info_cache
+from app.data_sources.circuit_breaker import CircuitBreaker, get_realtime_circuit_breaker
 from app.data_sources.factory import DataSourceFactory
-from app.data_sources.circuit_breaker import (
-    CircuitBreaker,
-    get_realtime_circuit_breaker
-)
-from app.data_sources.cache_manager import (
-    DataCache,
-    get_realtime_cache,
-    get_kline_cache,
-    get_stock_info_cache
-)
-from app.data_sources.rate_limiter import (
-    RateLimiter,
-    get_random_user_agent,
-    random_sleep,
-    retry_with_backoff
-)
+from app.data_sources.rate_limiter import RateLimiter, get_random_user_agent, random_sleep, retry_with_backoff
 
 __all__ = [
     # factory
-    'DataSourceFactory',
+    "DataSourceFactory",
     # fuse
-    'CircuitBreaker',
-    'get_realtime_circuit_breaker',
+    "CircuitBreaker",
+    "get_realtime_circuit_breaker",
     # cache
-    'DataCache',
-    'get_realtime_cache',
-    'get_kline_cache',
-    'get_stock_info_cache',
+    "DataCache",
+    "get_realtime_cache",
+    "get_kline_cache",
+    "get_stock_info_cache",
     # current limiter
-    'RateLimiter',
-    'get_random_user_agent',
-    'random_sleep',
-    'retry_with_backoff',
+    "RateLimiter",
+    "get_random_user_agent",
+    "random_sleep",
+    "retry_with_backoff",
 ]