feat: Make MAX_TOKENS and MAX_RESPONSE_SEGMENTS configurable

Added MAX_TOKENS and MAX_RESPONSE_SEGMENTS to .env.example and documentation. Updated constants to read from environment variables, allowing configuration of token and response segment limits.

.env.example

@@ -10,6 +10,10 @@ OPERATING_ENV=production
 STORAGE_DIR=/public/uploads
 # Maximum upload size for attachments
 MAX_UPLOAD_SIZE_MB=5
+# The number of segments when reaching the maximum Tokens count
+MAX_RESPONSE_SEGMENTS=5
+# Default token usage for a single chat
+MAX_TOKENS=8000
 
 # Example Context Values for qwen2.5-coder:32b
 #