a11y: aria-pressed for all pill groups, aria-label on search inputs and buttons

- Add role="group" + aria-label to duration-pills and sev-pills containers
- Add aria-pressed to severity filter, duration, and refresh-interval pills
- Keep aria-pressed in sync with JS (setDuration, applyRefreshPillUI, modal reset)
- Add aria-label to events-search, host-search, links-search inputs
- Add aria-label to host and UniFi device suppress buttons in templates
- Replace dynamic style color strings in links.html stat cards with TDS
  utility classes (lt-text-red/green/amber) via downCls/errCls variables

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

templates/links.html

@@ -17,7 +17,8 @@
   <div class="lt-toolbar-left">
     <div class="lt-search">
       <input type="search" class="lt-input lt-search-input" id="links-search"
-             placeholder="Filter by host or switch name…" autocomplete="off">
+             placeholder="Filter by host or switch name…" autocomplete="off"
+             aria-label="Filter by host or switch name">
     </div>
   </div>
   <div class="lt-toolbar-right">
@@ -407,8 +408,8 @@ function buildLinkSummary(hosts, unifiSwitches) {
   }
   const allTotal = totalIfaces + swTotal;
   const allDown  = downIfaces  + swDown;
-  const downColor = allDown  > 0 ? 'var(--red)'   : 'var(--green)';
-  const errColor  = errIfaces > 0 ? 'var(--amber)' : 'var(--green)';
+  const downCls    = allDown  > 0 ? 'lt-text-red'   : 'lt-text-green';
+  const errCls     = errIfaces > 0 ? 'lt-text-amber' : 'lt-text-green';
   const downCardCls = allDown  > 0 ? ' lt-stat-card--alert' : '';
   const poeCard = totalPoe > 0 ? `
     <div class="lt-stat-card">
@@ -428,16 +429,16 @@ function buildLinkSummary(hosts, unifiSwitches) {
         </div>
       </div>
       <div class="lt-stat-card${downCardCls}">
-        <span class="lt-stat-icon" aria-hidden="true" style="color:${downColor}">●</span>
+        <span class="lt-stat-icon ${downCls}" aria-hidden="true">●</span>
         <div class="lt-stat-info">
-          <span class="lt-stat-value" style="color:${downColor}">${allDown}</span>
+          <span class="lt-stat-value ${downCls}">${allDown}</span>
           <span class="lt-stat-label">Ports Down</span>
         </div>
       </div>
       <div class="lt-stat-card">
-        <span class="lt-stat-icon" aria-hidden="true" style="color:${errColor}">▲</span>
+        <span class="lt-stat-icon ${errCls}" aria-hidden="true">▲</span>
         <div class="lt-stat-info">
-          <span class="lt-stat-value" style="color:${errColor}">${errIfaces}</span>
+          <span class="lt-stat-value ${errCls}">${errIfaces}</span>
           <span class="lt-stat-label">With Errors</span>
         </div>
       </div>