Fix: Escaped Backticks durch korrekte nested Template-Literale ersetzt

`...` innerhalb von ${}  Expressions ist kein valides JS und
verhinderte Variablen-Substitution + crashte das Script in manchen
Browsern, wodurch alle Quellen-Tabs nicht funktionierten.

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

src/static/js/source-health.js

@@ -173,7 +173,7 @@ function renderHealthDashboard() {
                   <td>${CHECK_TYPE_LABELS[c.check_type] || c.check_type}</td>
                   <td><span class="badge badge-health-${c.status}">${c.status === "error" ? "Fehler" : "Warnung"}</span></td>
                   <td class="text-secondary" style="max-width:250px;">${esc(c.message)}</td>
-                  <td>${c.status === "error" && c.check_type === "reachability" ? \`<button class="btn btn-secondary btn-small" data-source-id="\${c.source_id}" data-source-name="\${esc(c.name)}" onclick="searchFix(this)">Lösung suchen</button>\` : ""}</td>
+                  <td>${c.status === "error" && c.check_type === "reachability" ? `<button class="btn btn-secondary btn-small" data-source-id="${c.source_id}" data-source-name="${esc(c.name)}" onclick="searchFix(this)">Lösung suchen</button>` : ""}</td>
                 </tr>`,
                 )
                 .join("")}