feat: live charge limit, identity retunes, btop assets (product calls)

- Charge limit: udev GROUP=users on threshold; menu applies sysfs live
  and persists state; boot/AC oneshot prefers live theme-state.json.
- Look & Feel: Reset wallpaper (auto); Theme/next/night light already there.
- NVIDIA first-class wrappers deferred past v1 (keep #59 comments).
- Identity taste: white, lumon, hackerman, matte-black, miasma.
- Hand btop.theme for identity + boreal/executive-slate/neon-glass.

Verified: V0 contrast; V1 battery-charge-limit VM. V3 live sysfs on laptop.

themes/white.json

@@ -7,16 +7,16 @@
   "colors": {
     "base": "#ffffff",
     "mantle": "#d9d9d9",
-    "surface": "#ffffff",
+    "surface": "#f0f0f0",
     "overlay": "#c0c0c0",
     "text": "#000000",
-    "subtext": "#000000",
+    "subtext": "#404040",
     "muted": "#b5b5b5",
     "accent": "#6e6e6e",
     "accentAlt": "#2e2e2e",
-    "good": "#3a3a3a",
-    "warn": "#4a4a4a",
-    "bad": "#2a2a2a"
+    "good": "#555555",
+    "warn": "#777777",
+    "bad": "#222222"
   },
   "border": {
     "active": "accent",