theme: soften the YoRHa shapes; SUPER+D opens the dashboard

The square markers, block meters and hard-cornered fills read as boxy
next to the porthole. The desktop is now soft throughout: the porthole
is the shape everything is built around and every smaller surface echoes
it.

- Theme gains radiusS / radiusM / radiusL. radiusL is frameRadius - padS,
  so anything inset padS inside one of the frame's curves is concentric
  with it.
- P5Panel and Skew draw rounded rectangles (Geom.roundedRect) whenever
  they neither lean nor are chopped, which is always now; the polygon
  path is kept for shapes brought back on purpose.
- Markers are dots; workspace pips, toggles, transport and media chips,
  notification actions and today's date are pills or discs; the slider
  handle is round. Meters are one continuous rounded line that glides to
  its level instead of a row of segments.
- Album art is rounded with ClippingRectangle in the bar, the media
  popout and the dashboard.
- Free-standing panels (launcher, ask) drop the corner brackets and take
  the frame radius.
- Fix: a hovered notification's wash was a full-bleed square, so in the
  drawer's bottom corner it ran past the drawer's curve. It is inset by
  padS/2 and rounded by radiusL, which keeps it inside the curve.

Hyprland: the discord special workspace and its window rule are gone,
SUPER+S stays the only scratchpad, and SUPER+D now opens the dashboard
(it was on SUPER+I).

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

quickshell/config/Theme.qml

@@ -190,9 +190,8 @@ Singleton {
     readonly property int frame: 8
     readonly property int frameRadius: 18
 
-    // Nothing leans and nothing is chopped. NieR panels are plain rectangles;
-    // their character comes from hairlines, square markers and corner ticks.
-    // Both knobs are kept so the shape code still has one place to ask.
+    // Nothing leans and nothing is chopped. Both knobs are kept so the shape
+    // code still has one place to ask.
     readonly property real skew: 0
     readonly property int cut: 0
     readonly property int stroke: 1
@@ -202,8 +201,21 @@ Singleton {
     readonly property real dropOffset: 0
     readonly property real keylineWidth: 0
 
-    // The square bullet that marks the current row, and the length of the
-    // corner ticks that frame a panel.
+    // Corners. Everything is soft — the porthole is the shape the whole
+    // desktop is built around, and every smaller surface is a gentler echo of
+    // it rather than a hard block.
+    //
+    //   radiusS  pills and small chips: buttons, tags, meter tracks
+    //   radiusM  rows and panels inside a surface
+    //   radiusL  anything that sits a padS inside the frame's own curve:
+    //            frameRadius - padS, so its corner is concentric with the
+    //            corner it sits in and the gap between them stays even
+    readonly property int radiusS: 6
+    readonly property int radiusM: 10
+    readonly property int radiusL: frameRadius - padS
+
+    // The dot that marks the current row, and the length of the corner
+    // ticks a panel can still ask for.
     readonly property int marker: 6
     readonly property int tick: 8