feat(arch-layer,scripts): linux-gated desktop configs + package install scripts

niri (exact_config.d, scripts), noctalia (plugins excluded — runtime
state with embedded token), fontconfig, mimeapps.list,
niri-dynamic-workspaces, systemd user unit files (enable-state not
managed; only nirinit enabled by run_once), niri-launch vendored from
/usr/bin (unowned hand-written script, shellcheck warnings pre-existing).

Scripts: packages (pacman --needed + paru, brew on darwin, root-safe,
keyed on packages.yaml hash), gh extensions (idempotent), user services
(linux), post (tpm clone, bat cache, fc-cache). All shellcheck-clean.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

dot_config/niri/config.kdl

@@ -0,0 +1,195 @@
+// ============================================================================
+// NIRI CONFIGURATION - Base for iNiR (ii)
+// ============================================================================
+// Minimal base config - customize to your needs
+// Wiki: https://github.com/YaLTeR/niri/wiki/Configuration:-Introduction
+// ============================================================================
+
+
+hotkey-overlay {
+    skip-at-startup
+}
+
+screenshot-path "~/Pictures/Screenshots/Screenshot from %Y-%m-%d %H-%M-%S.png"
+
+include "config.d/10-input-and-cursor.kdl"
+
+include "config.d/20-layout-and-overview.kdl"
+
+include "config.d/30-window-rules.kdl"
+
+include "config.d/40-environment.kdl"
+
+include "config.d/50-startup.kdl"
+
+include "config.d/60-animations.kdl"
+
+include "config.d/70-binds.kdl"
+
+include "config.d/80-layer-rules.kdl"
+
+include "config.d/90-outputs.kdl"
+
+// ============================================================================
+// Layer rules added by iNiR (required for backdrop in overview)
+// ============================================================================
+
+input {
+    keyboard {
+        xkb {
+            layout "us"
+        }
+        repeat-delay 400
+        repeat-rate 50
+    }
+    touchpad {
+        natural-scroll
+        tap
+        tap-button-map "left-right-middle"
+    }
+   
+    mod-key "Super"
+    mod-key-nested "Alt"
+}
+
+// ============================================================================
+// LAYOUT
+// ============================================================================
+
+layout {
+    background-color "transparent"
+    default-column-width { proportion 0.5; }
+
+    preset-column-widths {
+        proportion 0.33333
+        proportion 0.5
+        proportion 0.66667
+    }
+
+    focus-ring {
+        width 1.5
+        active-color "#7fc8ff"
+        inactive-color "transparent"
+    }
+
+    border {
+        off
+        width 1.5
+        active-color "#ffc87f"
+        inactive-color "transparent"
+        urgent-color "#9b0000"
+    }
+
+    shadow {
+        off
+        softness 30
+        spread 5
+        offset x=0 y=5
+        color "#0007"
+    }
+
+    tab-indicator {
+        place-within-column
+        hide-when-single-tab
+        position "left" // Can be "left", "right", "top", or "bottom"
+    }
+
+}
+
+gestures {
+    hot-corners {
+        off
+    }
+}
+
+cursor {
+    xcursor-theme "capitaine-cursors-light"
+    xcursor-size 24
+    hide-when-typing
+}
+
+overview {
+    zoom 0.4
+    workspace-shadow { off; }
+}
+// ============================================================================
+// WINDOW RULES
+// ============================================================================
+
+window-rule {
+    geometry-corner-radius 8
+    clip-to-geometry true
+}
+
+// ============================================================================
+// ANIMATIONS
+// ============================================================================
+// Tuned to complement quickshell's expressive Material motion curves
+// QS uses ~500ms for main movements, ~400ms enter, ~200ms exit
+
+animations {
+    workspace-switch {
+        spring damping-ratio=0.78 stiffness=1350 epsilon=0.0001
+    }
+    window-open {
+        spring damping-ratio=0.82 stiffness=1125 epsilon=0.0001
+    }
+    window-close {
+        spring damping-ratio=0.88 stiffness=2025 epsilon=0.0001
+    }
+    horizontal-view-movement {
+        spring damping-ratio=0.80 stiffness=1238 epsilon=0.0001
+    }
+    window-movement {
+        spring damping-ratio=0.85 stiffness=1463 epsilon=0.0001
+    }
+    window-resize {
+        spring damping-ratio=0.88 stiffness=1575 epsilon=0.0001
+    }
+    config-notification-open-close {
+        spring damping-ratio=0.90 stiffness=1800 epsilon=0.0001
+    }
+    screenshot-ui-open {
+        spring damping-ratio=0.85 stiffness=1688 epsilon=0.0001
+    }
+}
+
+// ============================================================================
+// ENVIRONMENT
+// ============================================================================
+
+environment {
+    XDG_CURRENT_DESKTOP "niri"
+    XDG_MENU_PREFIX "plasma-"  // Required for Dolphin/KDE app file associations
+    QT_QPA_PLATFORM "wayland"
+    ELECTRON_OZONE_PLATFORM_HINT "auto"
+    QT_LOGGING_RULES "quickshell.dbus.properties=false"
+    
+    // Qt theming: kde platform reads colors from kdeglobals (requires plasma-integration pkg)
+    // The installer falls back to qt6ct only if plasma-integration is not installed
+    QT_QPA_PLATFORMTHEME "kde"
+    QT_STYLE_OVERRIDE "Darkly"
+    
+    // Quickshell Python virtual environment
+    INIR_VENV "$HOME/.local/state/quickshell/.venv"
+    ILLOGICAL_IMPULSE_VIRTUAL_ENV "$HOME/.local/state/quickshell/.venv"
+}
+
+// ============================================================================
+// STARTUP — commands live in config.d/50-startup.kdl
+// ============================================================================
+
+// Noctalia v5: allows notification actions and window activation from Noctalia.
+debug {
+    honor-xdg-activation-with-invalid-serial
+}
+
+
+// ============================================================================
+// KEYBINDINGS
+// ============================================================================
+
+
+include "./noctalia.kdl"
+
+prefer-no-csd