Layout: resizable window, fluid SVG ring, no scrollbars unless overflow, opaque bg

tauri.conf: resizable=true, min 220x240, default 300x320.
BlockRing: SVG scales via viewBox, claims remaining vertical space.
#app uses flex column with sections flex:0 0 auto — content reflows when window resized.
Bumped --bg opacity from 0.78 to 0.93 so files behind the widget don't bleed through.
Themed scrollbars subtle when they do appear.

src-tauri/tauri.conf.json

@@ -14,11 +14,11 @@
       {
         "label": "main",
         "title": "Claude Usage",
-        "width": 280,
-        "height": 360,
-        "minWidth": 280,
-        "minHeight": 360,
-        "resizable": false,
+        "width": 300,
+        "height": 320,
+        "minWidth": 220,
+        "minHeight": 240,
+        "resizable": true,
         "decorations": false,
         "transparent": true,
         "alwaysOnTop": true,