feat(agent): métriques CPU, RAM, réseau, uptime

Implémentation complète des 4 modules sysinfo 0.30 (sans default-features).
- cpu: moyenne sur tous les cœurs via refresh_cpu_usage()
- memory: used/free/total via System
- network: total_received/total_transmitted via Networks
- uptime: System::uptime() statique
10 tests unitaires passent.

agent/src/metrics/cpu.rs

@@ -1,3 +1,26 @@
-pub fn get(_sys: &sysinfo::System) -> f32 {
-    0.0
+use sysinfo::System;
+
+pub fn get(sys: &System) -> f32 {
+    let cpus = sys.cpus();
+    if cpus.is_empty() {
+        return 0.0;
+    }
+    let total: f32 = cpus.iter().map(|c| c.cpu_usage()).sum();
+    total / cpus.len() as f32
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use sysinfo::System;
+
+    #[test]
+    fn test_cpu_in_range() {
+        let mut sys = System::new();
+        sys.refresh_cpu_usage();
+        std::thread::sleep(std::time::Duration::from_millis(200));
+        sys.refresh_cpu_usage();
+        let val = get(&sys);
+        assert!(val >= 0.0 && val <= 100.0, "CPU hors plage : {}", val);
+    }
 }

agent/src/metrics/memory.rs

@@ -1,3 +1,20 @@
-pub fn get(_sys: &sysinfo::System) -> (u64, u64, u64) {
-    (0, 0, 0)
+use sysinfo::System;
+
+pub fn get(sys: &System) -> (u64, u64, u64) {
+    (sys.used_memory(), sys.free_memory(), sys.total_memory())
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use sysinfo::System;
+
+    #[test]
+    fn test_memory_coherent() {
+        let mut sys = System::new();
+        sys.refresh_memory();
+        let (used, free, total) = get(&sys);
+        assert!(total > 0, "Total mémoire nul");
+        assert!(used + free <= total + 1024 * 1024, "used + free > total");
+    }
 }

agent/src/metrics/network.rs

@@ -1,5 +1,23 @@
 use sysinfo::Networks;
 
-pub fn get(_nets: &Networks) -> (u64, u64) {
-    (0, 0)
+pub fn get(networks: &Networks) -> (u64, u64) {
+    let rx: u64 = networks.iter().map(|(_, n)| n.total_received()).sum();
+    let tx: u64 = networks.iter().map(|(_, n)| n.total_transmitted()).sum();
+    (rx, tx)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use sysinfo::Networks;
+
+    #[test]
+    fn test_network_values_non_negative() {
+        let mut nets = Networks::new_with_refreshed_list();
+        nets.refresh();
+        let (rx, tx) = get(&nets);
+        // Les compteurs cumulatifs sont toujours >= 0 (u64)
+        let _ = rx;
+        let _ = tx;
+    }
 }

agent/src/metrics/uptime.rs

@@ -1,3 +1,12 @@
 pub fn get() -> u64 {
-    0
+    sysinfo::System::uptime()
+}
+
+#[cfg(test)]
+mod tests {
+    #[test]
+    fn test_uptime_positif() {
+        let up = super::get();
+        assert!(up > 0, "uptime nul ou négatif");
+    }
 }