refact!: prepare for transfer

apply @sgoudham's suggestions
ref https://github.com/catppuccin/catppuccin/issues/2696#issuecomment-2707252468

changes:
- removed every styling outside of the colors themselves (i.e. rounding,
  `text-shadow` & `padding`)
- changed the default accent color to `mauve`
- renamed flavour CSS filenames from `<f>.css` to `catppuccin-<f>.css`

Signed-off-by: Adam Perkowski <adas1per@protonmail.com>

jellyfin.tera

@@ -3,7 +3,7 @@ whiskers:
   version: 2.5.1
   matrix:
     - flavor
-  filename: 'themes/{{flavor.identifier}}.css'
+  filename: 'themes/catppuccin-{{flavor.identifier}}.css'
 ---
 :root {
   --rosewater: #{{rosewater.hex}};
@@ -21,7 +21,7 @@ whiskers:
   --blue: #{{blue.hex}};
   --lavender: #{{lavender.hex}};
 
-  --main-color: var(--sapphire);
+  --main-color: var(--mauve);
   --main-background: #{{base.hex}};
   --second-background: #{{mantle.hex}};
   --hover-background: #{{surface0.hex}};