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/executive-slate/btop.theme

@@ -0,0 +1,25 @@
+theme[main_bg]="#191C24"
+theme[main_fg]="#D7DDEA"
+theme[title]="#D7DDEA"
+theme[hi_fg]="#5A8AE6"
+theme[selected_bg]="#3E4759"
+theme[selected_fg]="#D7DDEA"
+theme[inactive_fg]="#5C6578"
+theme[graph_text]="#9AA5BB"
+theme[meter_bg]="#2A3040"
+theme[proc_misc]="#86A9F2"
+theme[cpu_box]="#5A8AE6"
+theme[mem_box]="#6FAE72"
+theme[net_box]="#86A9F2"
+theme[proc_box]="#2A3040"
+theme[div_line]="#3E4759"
+theme[temp_start]="#6FAE72"
+theme[temp_mid]="#DBA85A"
+theme[temp_end]="#D06B71"
+theme[cpu_start]="#6FAE72"
+theme[cpu_mid]="#DBA85A"
+theme[cpu_end]="#D06B71"
+theme[free_start]="#6FAE72"
+theme[used_start]="#DBA85A"
+theme[download_start]="#5A8AE6"
+theme[upload_start]="#86A9F2"