perf: move temperature polling into nova-stats daemon; Temperature.qml is now pure display

stats-daemon/src/main.rs

@@ -93,6 +93,23 @@ fn read_stat() -> Vec<Sample> {
     parse_stat(&fs::read_to_string("/proc/stat").unwrap_or_default())
 }
 
+fn read_temp_celsius() -> Option<i32> {
+    let mut max: Option<i32> = None;
+    for i in 0.. {
+        let path = format!("/sys/class/thermal/thermal_zone{i}/temp");
+        match fs::read_to_string(&path) {
+            Ok(s) => {
+                if let Ok(millic) = s.trim().parse::<i32>() {
+                    let c = millic / 1000;
+                    max = Some(max.map_or(c, |m: i32| m.max(c)));
+                }
+            }
+            Err(_) => break,
+        }
+    }
+    max
+}
+
 fn read_core_freqs() -> Vec<f64> {
     let mut freqs = Vec::new();
     for i in 0.. {
@@ -148,6 +165,12 @@ fn emit_cpu(out: &mut impl Write, prev: &[Sample], curr: &[Sample], freqs: &[f64
     let _ = writeln!(out, "]}}");
 }
 
+fn emit_temp(out: &mut impl Write) {
+    if let Some(c) = read_temp_celsius() {
+        let _ = writeln!(out, "{{\"type\":\"temp\",\"celsius\":{c}}}");
+    }
+}
+
 fn emit_mem(out: &mut impl Write) {
     let content = fs::read_to_string("/proc/meminfo").unwrap_or_default();
     if let Some(m) = parse_meminfo(&content) {
@@ -190,6 +213,7 @@ fn main() {
 
         if tick.is_multiple_of(2) {
             emit_mem(&mut out);
+            emit_temp(&mut out);
         }
 
         let _ = out.flush();