CPU reductions (same charts/features)

Cache cpuidle names (was re-reading name sysfs every tick × cores)
Cache CPU sysfs dir list + register cpufreq/throttle once
Map for per-core prev lookups (was O(n²) .find)
Dedupe meminfo/vmstat once per tick
Cache iface speed/duplex/mtu/qlen (30s)
Cache inotify limits (30s)
Gate registerChart for IRQs, cpuidle, peardock mapped charts
Remove leftover profile() stderr timers
Cache os.cpus().length in docker collector
Grow fd-cache buffer past 64KB for /proc/interrupts etc.

test/metrics-more.test.js

@@ -28,6 +28,10 @@ test('host-more parsers', (t) => {
 })
 
 test('collector second tick includes deep/more charts on Linux', async (t) => {
+  if (process.platform !== 'linux') {
+    t.pass('linux-only')
+    return
+  }
   const c = new MetricsCollector({ intervalMs: 40 })
   /** @type {Set<string>} */
   const charts = new Set()