📦 build: add memory limit and session safeguard settings

.env.example

@@ -26,12 +26,16 @@ FORCE_GRAYSCALE=false
 
 # Max rendered width/height in characters.
 MAX_DIMENSION=512
+# Max rendered area (columns x rows); larger terminals are scaled down.
+MAX_TERMINAL_CELLS=256000
 
 # Memory budget in MB for the rendered-frame cache (0 disables caching).
 RENDER_CACHE_MB=256
 
 # Go soft memory limit; set below your container limit to avoid OOM kills.
 GOMEMLIMIT=1GiB
+# Docker Compose container memory limit. Leave headroom for mapped frame files.
+MEMORY_LIMIT=2g
 
 # Connection limits. New connections over a limit are dropped immediately.
 # Max simultaneous connections from a single client IP.
@@ -43,6 +47,8 @@ MAX_TOTAL_CONNECTIONS=1000
 MAX_AUTH_ATTEMPTS=3
 # SSH handshake deadline in ms (0 to disable).
 HANDSHAKE_TIMEOUT=30000
+# Maximum session lifetime in ms (0 to disable).
+SESSION_TIMEOUT=600000
 
 # Log attempted usernames/passwords.
 LOG_CREDENTIALS=true