Make flake self-contained - consolidate installer-replication

BREAKING CHANGE: Remove external dots-hyprland dependency

- Imported all essential configs from dots-hyprland/installer-replication
- Added complete configs/ directory with:
  - hypr/ - Hyprland configuration
  - quickshell/ - Quickshell widgets and config
  - applications/ - Application configurations
  - scripts/ - Utility scripts
  - matugen/ - Material You theming
- Updated flake.nix to use local ./configs instead of external repo
- Simplified update-flake script (removed external repo management)
- Updated README to reflect self-contained architecture
- All builds pass with local configurations

Benefits:
- No external repository dependencies
- Faster builds (no network dependencies)
- Version controlled configs in single repo
- Easier maintenance and development
- Complete installer replication in one place

configs/hypr/execs.conf.template

@@ -0,0 +1,29 @@
+# Startup executables for dots-hyprland
+
+# Core desktop components
+exec-once = @QUICKSHELL_BIN@ -c $qsConfig &
+exec-once = @HYPRIDLE_BIN@
+
+# Authentication and security
+exec-once = @GNOME_KEYRING_BIN@ --start --components=secrets
+exec-once = @POLKIT_AGENT_BIN@
+
+# System services
+exec-once = dbus-update-activation-environment --all
+exec-once = sleep 1 && dbus-update-activation-environment --systemd WAYLAND_DISPLAY XDG_CURRENT_DESKTOP
+
+# Input method
+@INPUT_METHOD_EXEC@
+
+# Audio system
+@AUDIO_EXEC@
+
+# Clipboard management
+exec-once = @WL_PASTE_BIN@ --type text --watch @CLIPHIST_BIN@ store
+exec-once = @WL_PASTE_BIN@ --type image --watch @CLIPHIST_BIN@ store
+
+# Cursor theme
+exec-once = hyprctl setcursor @CURSOR_THEME@ @CURSOR_SIZE@
+
+# User custom execs
+@CUSTOM_EXECS@