Add static CPU model and core count to CPU collector

- Collect CPU model name and core count from /proc/cpuinfo
- Only collect once at startup (check if fields already set)
- Display below C-state row in dashboard CPU section
- Move CPU info collection from NixOS collector to CPU collector

shared/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "cm-dashboard-shared"
-version = "0.1.239"
+version = "0.1.240"
 edition = "2021"
 
 [dependencies]

shared/src/agent_data.rs

@@ -57,6 +57,11 @@ pub struct CpuData {
     pub temperature_celsius: Option<f32>,
     pub load_status: Status,
     pub temperature_status: Status,
+    // Static CPU information (collected once at startup)
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub model_name: Option<String>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub core_count: Option<u32>,
 }
 
 /// Memory monitoring data
@@ -219,6 +224,8 @@ impl AgentData {
                     temperature_celsius: None,
                     load_status: Status::Unknown,
                     temperature_status: Status::Unknown,
+                    model_name: None,
+                    core_count: None,
                 },
                 memory: MemoryData {
                     usage_percent: 0.0,