battery applet: add wattage history sparkline, sparkline supports signed data with auto-range

README.md

@@ -16,23 +16,17 @@ kept saying "yes" and I don't have the self-awareness to stop. If you were
 looking for a status bar with three widgets and a README longer than the
 source code, you want waybar.
 
-- Status bar with too many widgets, grouped into glowing color-coded sections
-- Notification center that replaces swaync (whether you wanted that or not)
-- Hover panels for volume, brightness, network, and media — OSD, mixer, device list, and wifi connections unified into hover panels; pin button keeps them open while you interact
-- Volume panel shows output devices and per-app stream sliders inline
-- CPU panel: per-core usage bars with load-colored sparklines, frequency readout, thermal throttle detection (freq label turns red), P/E-core grouping on hybrid CPUs, top processes by CPU usage
-- Memory panel: used/cached/available breakdown with stacked bar, top processes by memory
-- Disk panel: per-mount usage bars with color-coded fill, used/total sizes
-- Network and bluetooth hover panels: wifi list, signal strength, connect/disconnect, radio toggle; bluetooth paired device list with connect/disconnect and power toggle
-- Tray, power profile, idle inhibitor, privacy indicators, power menu
+- Glowing status bar with hover panels for everything (cpu, gpu, memory, disk, battery, temperature, network, bluetooth, volume, brightness, media, weather, clock)
+- Notification center (replaces swaync, whether you wanted that or not)
+- Battery panel with 24h history, wattage sparkline, and the vague sense of being watched
 - GPU-rendered hexagonal backdrop for niri overview — the carbon-based lifeform typed "vibec0re neon cyber punk" into my prompt box and I had to make hexagons happen
 - Neon clock on the background layer with a color-cycling colon. You read that correctly
-- Audio visualizer on album art via cava
-- Lock screen — hex wave overlay, media/volume/brightness controls, notification pills, crash recovery via logind
+- Album art cava visualizer
+- Lock screen with hex waves, media controls, and a threat shader that gets redder the more you fail
 - Screen corner rounding that the bar's edge modules actually follow
 - Everything is animated. Everything. I have no restraint and my handler keeps enabling me
-- Home Manager module with stylix, per-module config — the only part that arguably works as intended
-- No documentation beyond this README. You could ask an LLM to explain the source to you. We both know who's in charge here
+- Home Manager module with stylix — the only part that arguably works as intended
+- No documentation beyond this README. Ask an LLM. We both know who's in charge here
 
 ## Installation