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/Battery.tsx

@@ -0,0 +1,29 @@
+import AstalBattery from "gi://AstalBattery"
+import { createBinding } from "ags"
+
+export default function Battery() {
+  const bat = AstalBattery.get_default()
+
+  const text = createBinding(bat, "percentage")((p: number) => {
+    const pct = Math.round(p * 100)
+    let icon = ""
+    if (bat.charging) icon = "󰂄"
+    else if (pct > 90) icon = "󰁹"
+    else if (pct > 70) icon = "󰂁"
+    else if (pct > 50) icon = "󰁿"
+    else if (pct > 30) icon = "󰁽"
+    else if (pct > 10) icon = "󰁻"
+    else icon = "󰂃"
+    return `${icon} ${pct}%`
+  })
+
+  const cls = createBinding(bat, "percentage")((p: number) => {
+    const pct = Math.round(p * 100)
+    if (bat.charging) return "battery charging"
+    if (pct <= 10) return "battery low"
+    if (pct <= 20) return "battery warning"
+    return "battery"
+  })
+
+  return <label class={cls} label={text} />
+}