feat(wisdom): introduce wisdomSimpleSlice helper for package modules

Implement a `wisdomSimpleSlice` helper in `desktop/options.nix` to reduce
boilerplate for simple Home Manager modules that only manage packages.
This helper handles the `enable` option creation, platform-gating via
`availableOn`, and conditional inclusion in `home.packages`.

Refactor several existing wisdom modules to use this new helper:
- `wisdomBrowsersChrome`
- `wisdomBrowsersEdge`
- `wisdomEditorsKate`
- `wisdomEditorsObsidian`

Additionally, clean up `wisdom/default.nix` by removing the explicit
import of `wisdomShellBash` (which is now handled via auto-wiring) and
improving code formatting.

modules/wisdom/editors/obsidian.nix

@@ -1,21 +1,8 @@
-{ ... }: {
-  flake.homeManagerModules.wisdomEditorsObsidian =
-    { config, lib, pkgs, ... }:
-    let
-      root = config.chiasson.home;
-      cfg = config.chiasson.home.editors.obsidian;
-    in
-    {
-      options.chiasson.home.editors.obsidian.enable = lib.mkEnableOption ''
-        Obsidian (unfree); skipped if unavailable here.
-      '' // {
-        default = true;
-      };
-
-      config = lib.mkIf (root.enable && cfg.enable) {
-        home.packages = lib.optional (
-          lib.meta.availableOn pkgs.stdenv.hostPlatform pkgs.obsidian
-        ) pkgs.obsidian;
-      };
-    };
+{ self, ... }: {
+  flake.homeManagerModules.wisdomEditorsObsidian = self.lib.wisdomSimpleSlice {
+    path = "editors.obsidian";
+    default = true;
+    description = "Obsidian (unfree); skipped if unavailable here.";
+    packages = pkgs: [ pkgs.obsidian ];
+  };
 }