fix: restore environment variable support for key settings

- Re-enable DISCOVERY_SUBNET env var for Docker network configuration
- Re-enable LOG_LEVEL env var for runtime logging control
- Re-enable CONNECTION_TIMEOUT env var for timeout configuration
- Re-enable ALLOWED_ORIGINS env var for CORS configuration
- Update documentation to reflect working env vars

These env vars were accidentally disabled but are useful for Docker deployments.
Env vars override system.json settings when present.

Addresses #214 - user requested DISCOVERY_SUBNET env var support

README.md

@@ -128,16 +128,9 @@ services:
       # RIGHT: PULSE_AUTH_PASS='$$2a$$12$$hash...'
       # Or use a .env file where no escaping is needed
       
-      # Polling & timeouts
-      # - POLLING_INTERVAL=10               # Fixed at 10 seconds (matches Proxmox update cycle)
+      # Performance
       # - CONNECTION_TIMEOUT=10             # Connection timeout in seconds (default: 10)
       
-      # Updates
-      # - UPDATE_CHANNEL=stable             # Update channel: stable or rc (default: stable)
-      # - AUTO_UPDATE_ENABLED=false         # Enable auto-updates (default: false)
-      # - AUTO_UPDATE_CHECK_INTERVAL=24     # Hours between update checks (default: 24)
-      # - AUTO_UPDATE_TIME=03:00            # Time to install updates HH:MM (default: 03:00)
-      
       # CORS & logging
       # - ALLOWED_ORIGINS=https://app.example.com  # CORS origins (default: none, same-origin only)
       # - LOG_LEVEL=info                    # Log level: debug/info/warn/error (default: info)

docs/DOCKER.md

@@ -219,12 +219,12 @@ Common problems:
 | `PORT` | Web UI port | `7655` |
 | `ALLOWED_ORIGINS` | CORS origins | Same-origin only |
 | `DISCOVERY_SUBNET` | Network to scan | Auto-detect |
+| `CONNECTION_TIMEOUT` | Connection timeout (seconds) | `10` |
+| `LOG_LEVEL` | Logging verbosity | `info` |
 
 ### System
 | Variable | Description | Default |
 |----------|-------------|---------|
-| `POLLING_INTERVAL` | Check interval (seconds) | `10` |
-| `LOG_LEVEL` | Logging verbosity | `INFO` |
 | `TZ` | Timezone | `UTC` |
 
 ## Advanced Configuration

internal/config/config.go

@@ -385,8 +385,28 @@ func Load() (*Config, error) {
 			log.Info().Msg("Development mode: allowing localhost origins")
 		}
 	}
-	// REMOVED: LOG_LEVEL and DISCOVERY_SUBNET env vars
-	// These settings now ONLY come from system.json to prevent confusion
+	// Support env vars for important settings (override system.json)
+	if discoverySubnet := os.Getenv("DISCOVERY_SUBNET"); discoverySubnet != "" {
+		cfg.DiscoverySubnet = discoverySubnet
+		log.Info().Str("subnet", discoverySubnet).Msg("Discovery subnet set from DISCOVERY_SUBNET env var")
+	}
+	if logLevel := os.Getenv("LOG_LEVEL"); logLevel != "" {
+		cfg.LogLevel = logLevel
+		log.Info().Str("level", logLevel).Msg("Log level set from LOG_LEVEL env var")
+	}
+	if connectionTimeout := os.Getenv("CONNECTION_TIMEOUT"); connectionTimeout != "" {
+		if d, err := time.ParseDuration(connectionTimeout + "s"); err == nil {
+			cfg.ConnectionTimeout = d
+			log.Info().Dur("timeout", d).Msg("Connection timeout set from CONNECTION_TIMEOUT env var")
+		} else if d, err := time.ParseDuration(connectionTimeout); err == nil {
+			cfg.ConnectionTimeout = d
+			log.Info().Dur("timeout", d).Msg("Connection timeout set from CONNECTION_TIMEOUT env var")
+		}
+	}
+	if allowedOrigins := os.Getenv("ALLOWED_ORIGINS"); allowedOrigins != "" {
+		cfg.AllowedOrigins = allowedOrigins
+		log.Info().Str("origins", allowedOrigins).Msg("Allowed origins set from ALLOWED_ORIGINS env var")
+	}
 	
 	// Set log level
 	switch cfg.LogLevel {