feat(quickshell): notifications as a NieR message log in a corner drawer

Notifications were still Persona: separate floating cards with an urgency
slash down the leading edge, action chips that filled with the accent on
hover, and a 60px shove in from the right.

NotifCard is now laid out like an entry in NieR's message log: a square
urgency marker and the sender's name running into a hairline, the summary
and body set in from the marker, and hairline action buttons with their
own small marker that lift on hover instead of inverting. It draws no
panel; rest is bare and hover lifts the row onto the surface tone.
Critical entries take the red into the marker and the sender line only.

The toast stack is one hull drawer docked into the opening's top-right
corner — off the bar through one fillet, onto the rail through the other,
the same construction as a corner-docked popout. It grows with its
entries and slides back behind the frame when the last one goes. Each
entry's countdown is a hairline along its foot, and new entries fade in
place. The history popout lists the same entries flush.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

quickshell/popouts/NotifPopout.qml

@@ -68,7 +68,8 @@ Popout {
             anchors.right: parent.right
             anchors.bottom: parent.bottom
             clip: true
-            spacing: Theme.padS
+            // Entries carry their own header hairline, so they sit flush.
+            spacing: 0
             model: Notifs.history
 
             delegate: NotifCard {
@@ -79,12 +80,6 @@ Popout {
             }
 
             add: Transition {
-                NumberAnimation {
-                    properties: "x"
-                    from: 40
-                    duration: Theme.durSlow
-                    easing.type: Easing.OutCubic
-                }
                 NumberAnimation {
                     property: "opacity"
                     from: 0; to: 1