apply stylelint auto fixes (#5940)

## Summary

Applied stylelint auto-fixes and resolved manual CSS issues across 25
files to achieve full compliance with stylelint rules.

## Changes

- **What**: Auto-fixed 68 CSS issues (legacy color functions,
font-weight keywords, shorthand properties, pseudo-element notation) and
manually resolved 6 remaining issues (duplicate selectors, vendor prefix
duplicates, font fallbacks, Vue v-bind whitelisting)
- **Config**: Disabled `no-descending-specificity` rule (43 warnings
require architectural CSS refactor)

## Review Focus

Verify no visual regressions from modernized CSS syntax:
- Modern [color function
notation](https://www.w3.org/TR/css-color-4/#funcdef-rgb): `rgba(0, 0,
0, 0.5)` → `rgb(0 0 0 / 50%)`
- Numeric font weights: `bold`/`normal` → `700`/`400`
- Pseudo-element double colons: `:before` → `::before

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-5940-apply-stylelint-auto-fixes-2846d73d365081ee8031c212a69a4bd4)
by [Unito](https://www.unito.io)

---------

Co-authored-by: DrJKL <DrJKL0424@gmail.com>

apps/desktop-ui/src/components/install/InstallLocationPicker.vue

@@ -286,6 +286,12 @@ const onFocus = async () => {
     .p-accordionheader {
       @apply rounded-t-xl rounded-b-none;
     }
+
+    .p-accordionheader-toggle-icon {
+      &::before {
+        content: '\e902';
+      }
+    }
   }
 
   .p-accordioncontent {
@@ -302,13 +308,5 @@ const onFocus = async () => {
       content: '\e933';
     }
   }
-
-  .p-accordionpanel-active {
-    .p-accordionheader-toggle-icon {
-      &::before {
-        content: '\e902';
-      }
-    }
-  }
 }
 </style>

apps/desktop-ui/src/views/DesktopUpdateView.vue

@@ -65,12 +65,12 @@ onUnmounted(() => electron.Validation.dispose())
 
 .download-bg::before {
   @apply m-0 absolute text-muted;
-  font-family: 'primeicons';
+  font-family: 'primeicons', sans-serif;
   top: -2rem;
   right: 2rem;
   speak: none;
   font-style: normal;
-  font-weight: normal;
+  font-weight: 400;
   font-variant: normal;
   text-transform: none;
   line-height: 1;

apps/desktop-ui/src/views/MaintenanceView.vue

@@ -186,12 +186,12 @@ onUnmounted(() => electron.Validation.dispose())
 
 .backspan::before {
   @apply m-0 absolute text-muted;
-  font-family: 'primeicons';
+  font-family: 'primeicons', sans-serif;
   top: -2rem;
   right: -2rem;
   speak: none;
   font-style: normal;
-  font-weight: normal;
+  font-weight: 400;
   font-variant: normal;
   text-transform: none;
   line-height: 1;

apps/desktop-ui/src/views/ServerStartView.vue

@@ -18,16 +18,16 @@
         style="
           background: radial-gradient(
             ellipse 800px 600px at center,
-            rgba(23, 23, 23, 0.95) 0%,
-            rgba(23, 23, 23, 0.93) 10%,
-            rgba(23, 23, 23, 0.9) 20%,
-            rgba(23, 23, 23, 0.85) 30%,
-            rgba(23, 23, 23, 0.75) 40%,
-            rgba(23, 23, 23, 0.6) 50%,
-            rgba(23, 23, 23, 0.4) 60%,
-            rgba(23, 23, 23, 0.2) 70%,
-            rgba(23, 23, 23, 0.1) 80%,
-            rgba(23, 23, 23, 0.05) 90%,
+            rgb(23 23 23 / 0.95) 0%,
+            rgb(23 23 23 / 0.93) 10%,
+            rgb(23 23 23 / 0.9) 20%,
+            rgb(23 23 23 / 0.85) 30%,
+            rgb(23 23 23 / 0.75) 40%,
+            rgb(23 23 23 / 0.6) 50%,
+            rgb(23 23 23 / 0.4) 60%,
+            rgb(23 23 23 / 0.2) 70%,
+            rgb(23 23 23 / 0.1) 80%,
+            rgb(23 23 23 / 0.05) 90%,
             transparent 100%
           );
         "