Add Noctalia shell with Quickshell overview

- Add `noctalia` input to flake and lock it in `flake.lock`.
- Include `noctalia` and `quickshell` modules in `flake.nix`.
- Extend core packages to accept `inputs` and `system`; add
  `quickshell.nix`
  with required Qt6 packages and environment variables.
- Enable `upower` service for battery handling.
- Add home modules `noctalia.nix` and `overview.nix` (QML UI, README,
  assets, widgets, services) to provide a workspace overview.
- Comment out unused rofi and web‑search binds; update `exec‑once` to
  start
  the overview daemon and `noctalia-shell`.
- Provide `restart.noctalia` script and its Nix wrapper.
- Enable `noctalia-shell` in `stylix` configuration.

flake.lock

@@ -487,6 +487,26 @@
         "type": "github"
       }
     },
+    "noctalia": {
+      "inputs": {
+        "nixpkgs": [
+          "nixpkgs"
+        ]
+      },
+      "locked": {
+        "lastModified": 1769983098,
+        "narHash": "sha256-PKej3N1BxAoKzusrdWuS9gT8bXW0U/Zk8RkedsP3qYc=",
+        "owner": "noctalia-dev",
+        "repo": "noctalia-shell",
+        "rev": "2a98d04b2f5e251935ba296c0d7dc374bdc5e32d",
+        "type": "github"
+      },
+      "original": {
+        "owner": "noctalia-dev",
+        "repo": "noctalia-shell",
+        "type": "github"
+      }
+    },
     "nur": {
       "inputs": {
         "flake-parts": [
@@ -569,6 +589,7 @@
         "home-manager": "home-manager",
         "nix-flatpak": "nix-flatpak",
         "nixpkgs": "nixpkgs",
+        "noctalia": "noctalia",
         "prismlauncher-cracked": "prismlauncher-cracked",
         "stylix": "stylix",
         "wrappers": "wrappers"