fix(web): repair garbled Advanced Hardware section description

An earlier sed-based text update concatenated the old and new copies of
this description instead of replacing one with the other, leaving a
duplicated sentence with the — entity broken into ".mdash;" (visible
as literal "mdash;" text on the page). Restored to one clean sentence.

Other findings from this review were already fixed in a prior commit
(installedPlugins setter) or are confirmed dead code with zero live
callers (executePluginAction/dotToNested/entity-unescape/generateFieldHtml,
all reachable only from the two unused savePluginConfig copies in
app-shell.js - grepped every template, no references) - same legacy
cluster flagged in earlier review passes, still queued for a dedicated
deletion follow-up rather than patched in place here.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01KEZK1P1Q1fu5pcuVrkrCFZ

web_interface/templates/v3/partials/display.html

@@ -144,7 +144,7 @@
                         <h4 class="font-semibold text-gray-900">
                             <i class="fas fa-sliders-h mr-1 text-gray-500"></i>Advanced Hardware &amp; Display Options (15)
                         </h4>
-                        <p class="text-sm text-gray-600 mt-1">Multiplexing, panel variants, PWM tuning, and display options Multiplexing, panel variants, and PWM tuning &mdash; the defaults work for standard HUB75 panels.mdash; the defaults work for standard HUB75 panels.</p>
+                        <p class="text-sm text-gray-600 mt-1">Multiplexing, panel variants, PWM tuning, and display options &mdash; the defaults work for standard HUB75 panels.</p>
                     </div>
                     <i id="display-section-advanced-hardware-icon" class="fas fa-chevron-right text-gray-500 transition-transform"></i>
                 </button>