style: mystical purple primary + container-fluid full-width

- Override Bootstrap 5.3 dark-theme --bs-primary to #8b5cf6 (violet)
- Update rcon.css accent, sidebar, and focus-ring to match purple
- Switch all containers from fixed-width to container-fluid

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

rcon.css

@@ -3,7 +3,7 @@
 :root {
   --rcon-bg: #252830;
   --rcon-text: #cfd2da;
-  --rcon-accent: #1ca8dd;
+  --rcon-accent: #a78bfa;
   --rcon-card-bg: #434857;
   /* Override BS5 dark theme body background */
   --bs-body-bg: #252830;
@@ -41,7 +41,7 @@ a:hover { color: #fff; text-decoration: none; }
 .nav-sidebar .nav-link:hover,
 .nav-sidebar .nav-link.active {
   color: #fff;
-  background-color: #428bca;
+  background-color: #8b5cf6;
 }
 
 /* Fade utility */
@@ -78,7 +78,7 @@ a:hover { color: #fff; text-decoration: none; }
   background: rgba(255, 255, 255, 0.2);
   color: #fff;
   border-color: var(--rcon-accent);
-  box-shadow: 0 0 0 0.2rem rgba(28, 168, 221, 0.25);
+  box-shadow: 0 0 0 0.2rem rgba(139, 92, 246, 0.25);
 }
 
 /* Cards — override BS dark-theme bg to our darker shade */