feat: Ghost Shell v2 — AGS v3 statusbar + violet-chaton v2 palette

- AGS v3.1.0 (Astal/GTK3) Ghost Shell avec ghost mode (heartbeat + hover reveal)
- Modules : clock, battery, volume (interactif), network, MPRIS, CPU/RAM, systray
- Brain Power panel (Super + B) — lecture live focus/todos/session
- tetardtek_ prompt avec curseur clignotant
- Palette violet-chaton v2 documentée (Mitsuri Kanroji gradient magenta → green)
- Autostart COSMIC via .desktop
- Archive AGS v1 conservée pour référence

ags-v3/widget/modules/SystemStats.tsx

@@ -0,0 +1,31 @@
+import { createPoll } from "ags/time"
+import { exec } from "ags/process"
+
+function getCpuUsage(): string {
+  try {
+    const out = exec("bash -c \"top -bn1 | grep 'Cpu(s)' | awk '{print 100 - $8}'\"")
+    return `${Math.round(parseFloat(out))}`
+  } catch {
+    return "?"
+  }
+}
+
+function getRamUsage(): string {
+  try {
+    return exec("bash -c \"free | awk '/Mem:/ {printf \\\"%.0f\\\", $3/$2 * 100}'\"")
+  } catch {
+    return "?"
+  }
+}
+
+export default function SystemStats() {
+  const cpu = createPoll("0", 3000, () => getCpuUsage())
+  const ram = createPoll("0", 5000, () => getRamUsage())
+
+  return (
+    <box>
+      <label class="cpu module" label={cpu((v: string) => ` ${v}%`)} />
+      <label class="ram module" label={ram((v: string) => `󰍛 ${v}%`)} />
+    </box>
+  )
+}