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/exact_config.d/30-window-rules.kdl

@@ -0,0 +1,135 @@
+// ============================================================================
+// WINDOW RULES
+// ============================================================================
+
+window-rule {
+    geometry-corner-radius 10
+    clip-to-geometry true
+}
+
+window-rule {
+  background-effect {
+    blur true
+    xray false
+  }
+}
+
+// Noctalia v5: floating settings window.
+window-rule {
+    match app-id="dev.noctalia.Noctalia"
+    open-floating true
+    default-column-width { fixed 1080; }
+    default-window-height { fixed 920; }
+}
+
+blur {
+    passes 4
+    offset 5.0
+    noise 0.02
+    saturation 2.0
+}
+
+window-rule {
+    match app-id="Folo"
+    match app-id="Spotify"
+    match app-id="zen"
+    match app-id="brave-origin-nightly"
+    match app-id="gemini-desktop"
+    match app-id="claude-desktop"
+    opacity 0.9
+    open-floating false
+    draw-border-with-background false
+    background-effect {
+        blur true
+        xray false
+    }
+    open-focused true
+}
+
+window-rule {
+    match app-id="kitty"
+    match app-id="zed"
+    match app-id="obsidian"
+    match app-id="Beeper"
+    match app-id="chromium"
+    match app-id="com.mitchellh.ghostty"
+    opacity 0.9
+    open-floating false
+    draw-border-with-background false
+    open-focused true
+    background-effect {
+        blur true
+        xray false
+    }
+}
+
+window-rule {
+    match app-id="org.gnome.Nautilus"
+    match app-id="com.gabm.satty"
+    open-floating true
+    open-focused true
+    draw-border-with-background false
+    default-column-width { proportion 0.5; }
+}
+
+window-rule {
+    match app-id="kitty-dropdown"
+    open-floating true
+    opacity 1.0
+    default-floating-position x=32 y=32 relative-to="top"
+}
+
+window-rule {
+    match title="ostt"
+    open-floating true
+    open-focused true
+    default-column-width { proportion 0.1; }
+    default-window-height { proportion 0.15; }
+    opacity 0.8
+
+    draw-border-with-background false
+    default-floating-position x=64 y=64 relative-to="bottom-right"
+}
+
+
+window-rule {
+    match title="Picture-in-Picture" app-id="zen"
+    match title="Picture in picture"
+    open-floating true
+    open-focused false
+    opacity 1.0
+
+    // default-floating-position x=28 y=28 relative-to="top-right"
+    default-floating-position x=28 y=28 relative-to="bottom-left"
+    // open-on-output "eDP-1" 
+    open-on-output "HDMI-A-1"
+    // open-on-output "Apple Computer Inc StudioDisplay 0x984262A7"
+}
+
+window-rule {
+    // open-on-output "HDMI-A-1" 
+}
+
+window-rule {
+    match app-id="sticky-notest-canvas"
+    match title="Sticky Notes"
+    match app-id="vacuumtube"
+    match app-id="Fladder"
+    match app-id="gemini-desktop"
+    match app-id="com-fastmail-fastmail"
+    match app-id="Beeper"
+    match app-id="todoist"
+    match app-id="com.anthropic.Claude"
+    match app-id="Hermes"
+
+
+    open-on-output "eDP-1" 
+}
+
+window-rule {
+    match app-id="kitty"
+    match app-id="zed"
+    match app-id="obsidian"
+
+    open-on-output "Apple Computer Inc StudioDisplay 0x984262A7"
+}