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.

modules/home/scripts/restart.noctalia

@@ -0,0 +1,54 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+# Restart the Noctalia QuickShell session by terminating only the noctalia-shell
+# processes, avoiding any signals to unrelated process groups (e.g. Hyprland).
+
+log() { printf "[restart.noctalia] %s\n" "$*"; }
+
+list_target_pids() {
+  # Collect only PIDs whose command explicitly runs noctalia-shell
+  # - direct wrapper: ".../noctalia-shell"
+  # - quickshell/qs with "-c noctalia-shell"
+  ps -eo pid=,cmd= \
+    | ${GREP:-grep} -E "(^|/)(noctalia-shell)( |$)|(^| )((qs|quickshell))( | ).*-c( |=)?noctalia-shell( |$)" \
+    | awk '{print $1}'
+}
+
+terminate_targets() {
+  local pids left tries
+  mapfile -t pids < <(list_target_pids || true)
+
+  if ((${#pids[@]} > 0)); then
+    kill -TERM "${pids[@]}" 2>/dev/null || true
+  fi
+
+  # Wait up to ~3s for clean exit
+  for tries in {1..15}; do
+    mapfile -t left < <(list_target_pids || true)
+    ((${#left[@]} == 0)) && break
+    sleep 0.2
+  done
+
+  # Force kill leftovers only (do not touch anything else)
+  if ((${#left[@]} > 0)); then
+    kill -KILL "${left[@]}" 2>/dev/null || true
+  fi
+}
+
+start_noctalia() {
+  # Prefer the noctalia-shell wrapper to ensure proper env and runtime flags
+  if command -v noctalia-shell >/dev/null 2>&1; then
+    nohup setsid noctalia-shell >/dev/null 2>&1 &
+  elif command -v quickshell >/dev/null 2>&1; then
+    nohup setsid quickshell -c noctalia-shell >/dev/null 2>&1 &
+  elif command -v qs >/dev/null 2>&1; then
+    nohup setsid qs -c noctalia-shell >/dev/null 2>&1 &
+  else
+    echo "Error: noctalia-shell/quickshell/qs not found in PATH" >&2
+    exit 1
+  fi
+}
+
+terminate_targets
+start_noctalia