bos-settings 0.4.1: fix broken panels, add breadsearch view

- breadbox panel edited [[contexts]] but breadbox reads [[context]]
  (serde rename mismatch) — panel was always empty and Save appended
  a dead array.
- Packages panel parsed installed.json as a flat map instead of
  unwrapping {"packages": {...}} — always showed one bogus row.
- load_doc silently produced an empty document on any parse error,
  so the next Save could clobber a config file with a syntax typo;
  now backs it up first.
- Hyprland panel opened hyprland.conf/keybinds.conf (BOS ships
  hyprland.lua) via $EDITOR with no terminal (dead click for any TUI
  editor) and defaulted to foot (BOS ships kitty). Now opens
  hyprland.lua and a keybinds cheat sheet via kitty -e $EDITOR.
- New breadsearch view: power (enabled/run-on-battery), compute
  backend (cpu/npu/rocm), index/search settings.

Cargo.lock

@@ -28,7 +28,7 @@ checksum = "b4388bee8683e3d04af747c73422af53102d2bd24d9eadb6cbc100baef4b43f8"
 
 [[package]]
 name = "bos-settings"
-version = "0.4.0"
+version = "0.4.1"
 dependencies = [
  "async-channel",
  "bread-theme",