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/Volume.tsx

@@ -0,0 +1,41 @@
+import AstalWp from "gi://AstalWp"
+import { createBinding } from "ags"
+
+export default function Volume() {
+  const speaker = AstalWp.get_default()!.defaultSpeaker!
+
+  const text = createBinding(speaker, "volume")((v: number) => {
+    const pct = Math.round(v * 100)
+    const muted = speaker.mute
+    let icon = "󰕾"
+    if (muted) icon = "󰝟"
+    else if (v > 0.66) icon = "󰕾"
+    else if (v > 0.33) icon = "󰖀"
+    else if (v > 0) icon = "󰕿"
+    else icon = "󰝟"
+    return `${icon} ${pct}%`
+  })
+
+  const cls = createBinding(speaker, "mute")((m: boolean) =>
+    m ? "volume muted" : "volume"
+  )
+
+  return (
+    <button
+      class={cls}
+      onClicked={() => {
+        speaker.mute = !speaker.mute
+      }}
+      onScroll={(_self: any, event: any) => {
+        const delta = event.delta_y
+        if (delta < 0) {
+          speaker.volume = Math.min(speaker.volume + 0.05, 1.0)
+        } else {
+          speaker.volume = Math.max(speaker.volume - 0.05, 0.0)
+        }
+      }}
+    >
+      <label label={text} />
+    </button>
+  )
+}