Remove hardcoded /tmp autodetection and implement proper tmpfs monitoring

- Remove /tmp autodetection from disk collector (57 lines removed)
- Add tmpfs monitoring to memory collector with get_tmpfs_metrics() method
- Generate memory_tmp_* metrics for proper RAM-based tmpfs monitoring
- Fix type annotations in tmpfs parsing for compilation
- System widget now correctly displays tmpfs usage in RAM section

agent/src/collectors/memory.rs

@@ -188,8 +188,98 @@ impl MemoryCollector {
             );
         }
 
+        // Monitor tmpfs (/tmp) usage
+        if let Ok(tmpfs_metrics) = self.get_tmpfs_metrics() {
+            metrics.extend(tmpfs_metrics);
+        }
+
         metrics
     }
+
+    /// Get tmpfs (/tmp) usage metrics  
+    fn get_tmpfs_metrics(&self) -> Result<Vec<Metric>, CollectorError> {
+        use std::process::Command;
+        
+        let output = Command::new("df")
+            .arg("--block-size=1")
+            .arg("/tmp")
+            .output()
+            .map_err(|e| CollectorError::SystemRead {
+                path: "/tmp".to_string(),
+                error: e.to_string(),
+            })?;
+
+        if !output.status.success() {
+            return Ok(Vec::new()); // Return empty if /tmp not available
+        }
+
+        let output_str = String::from_utf8(output.stdout)
+            .map_err(|e| CollectorError::Parse {
+                value: "df output".to_string(),
+                error: e.to_string(),
+            })?;
+
+        let lines: Vec<&str> = output_str.lines().collect();
+        if lines.len() < 2 {
+            return Ok(Vec::new());
+        }
+
+        let fields: Vec<&str> = lines[1].split_whitespace().collect();
+        if fields.len() < 4 {
+            return Ok(Vec::new());
+        }
+
+        let total_bytes: u64 = fields[1].parse()
+            .map_err(|e: std::num::ParseIntError| CollectorError::Parse {
+                value: fields[1].to_string(),
+                error: e.to_string(),
+            })?;
+        let used_bytes: u64 = fields[2].parse()
+            .map_err(|e: std::num::ParseIntError| CollectorError::Parse {
+                value: fields[2].to_string(),
+                error: e.to_string(),
+            })?;
+
+        let total_gb = total_bytes as f32 / (1024.0 * 1024.0 * 1024.0);
+        let used_gb = used_bytes as f32 / (1024.0 * 1024.0 * 1024.0);
+        let usage_percent = if total_bytes > 0 {
+            (used_bytes as f32 / total_bytes as f32) * 100.0
+        } else {
+            0.0
+        };
+
+        let mut metrics = Vec::new();
+        let timestamp = chrono::Utc::now().timestamp() as u64;
+
+        metrics.push(Metric {
+            name: "memory_tmp_usage_percent".to_string(),
+            value: MetricValue::Float(usage_percent),
+            unit: Some("%".to_string()),
+            description: Some("tmpfs /tmp usage percentage".to_string()),
+            status: Status::Ok,
+            timestamp,
+        });
+
+        metrics.push(Metric {
+            name: "memory_tmp_used_gb".to_string(),
+            value: MetricValue::Float(used_gb),
+            unit: Some("GB".to_string()),
+            description: Some("tmpfs /tmp used space".to_string()),
+            status: Status::Ok,
+            timestamp,
+        });
+
+        metrics.push(Metric {
+            name: "memory_tmp_total_gb".to_string(),
+            value: MetricValue::Float(total_gb),
+            unit: Some("GB".to_string()),
+            description: Some("tmpfs /tmp total space".to_string()),
+            status: Status::Ok,
+            timestamp,
+        });
+
+        Ok(metrics)
+    }
 }
 
 #[async_trait]