feat: add configurable log rotation settings via environment variables

• Add LOG_DIR env var for log file location
• Add LOG_MAX_BYTES for max log file size
• Add LOG_BACKUP_COUNT for backup count

.env.example

@@ -23,6 +23,9 @@
 ### Logging level
 # LOG_LEVEL=INFO
 # VERBOSE=False
+# LOG_DIR=/path/to/log/directory  # Log file directory path, defaults to current working directory
+# LOG_MAX_BYTES=10485760          # Log file max size in bytes, defaults to 10MB
+# LOG_BACKUP_COUNT=5              # Number of backup files to keep, defaults to 5
 
 ### Max async calls for LLM
 # MAX_ASYNC=4