fix(039): restore readable text on Servers "Scan All" button

The button used "btn btn-primary btn-outline" which in the current
DaisyUI theme collapses the text color onto the background, making
"Scan All" invisible except on hover (reported in both corporate and
business themes).

Match the styling of the other scan triggers (Security "Scan All
Servers", ServerDetail "Scan Now") by dropping btn-outline so the
button renders as a standard filled btn-primary with primary-content
text — readable in all themes.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: claude

frontend/src/views/Servers.vue

@@ -22,7 +22,7 @@
           v-if="hasEnabledScanners()"
           @click="scanAllServers"
           :disabled="scanAllRunning"
-          class="btn btn-primary btn-outline"
+          class="btn btn-primary"
         >
           <svg class="w-5 h-5" fill="none" stroke="currentColor" viewBox="0 0 24 24">
             <path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M9 12l2 2 4-4m5.618-4.016A11.955 11.955 0 0112 2.944a11.955 11.955 0 01-8.618 3.04A12.02 12.02 0 003 9c0 5.591 3.824 10.29 9 11.622 5.176-1.332 9-6.03 9-11.622 0-1.042-.133-2.052-.382-3.016z" />