initial check for process summary screen

This check in offers alpha support for per process metrics, you can view threads, process CPU usage over time, IO, memory, CPU time, parent process, command, uptime and journal entries. This is unfinished but all major functionality is available and I wanted to make it available to feedback and testing.

socktop_agent/src/state.rs

@@ -63,6 +63,11 @@ pub struct AppState {
     pub cache_metrics: Arc<Mutex<CacheEntry<crate::types::Metrics>>>,
     pub cache_disks: Arc<Mutex<CacheEntry<Vec<crate::types::DiskInfo>>>>,
     pub cache_processes: Arc<Mutex<CacheEntry<crate::types::ProcessesPayload>>>,
+
+    // Process detail caches (per-PID)
+    pub cache_process_metrics:
+        Arc<Mutex<HashMap<u32, CacheEntry<crate::types::ProcessMetricsResponse>>>>,
+    pub cache_journal_entries: Arc<Mutex<HashMap<u32, CacheEntry<crate::types::JournalResponse>>>>,
 }
 
 #[derive(Clone, Debug)]
@@ -71,6 +76,12 @@ pub struct CacheEntry<T> {
     pub value: Option<T>,
 }
 
+impl<T> Default for CacheEntry<T> {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
 impl<T> CacheEntry<T> {
     pub fn new() -> Self {
         Self {
@@ -90,6 +101,12 @@ impl<T> CacheEntry<T> {
     }
 }
 
+impl Default for AppState {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
 impl AppState {
     pub fn new() -> Self {
         let sys = System::new();
@@ -116,6 +133,8 @@ impl AppState {
             cache_metrics: Arc::new(Mutex::new(CacheEntry::new())),
             cache_disks: Arc::new(Mutex::new(CacheEntry::new())),
             cache_processes: Arc::new(Mutex::new(CacheEntry::new())),
+            cache_process_metrics: Arc::new(Mutex::new(HashMap::new())),
+            cache_journal_entries: Arc::new(Mutex::new(HashMap::new())),
         }
     }
 }