[feat](trx-frontend): bookmark markers, category colors, text filter

- Move bookmark frequency markers from drawSpectrum() to drawSignalOverlay()
  so dashed lines span both the waterfall and waveform canvases
- Assign distinct palette colors to named categories; uncategorised uses
  --accent-yellow resolved from the live theme at runtime
- Compute WCAG-compliant foreground color (dark/light) per category so label
  text is always legible against the solid background
- Add text search input to the Bookmarks toolbar; filters by name, category,
  and comment client-side without re-fetching from the server

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Signed-off-by: Stan Grams <sjg@haxx.space>

src/trx-client/trx-frontend/trx-frontend-http/assets/web/plugins/bookmarks.js

@@ -44,11 +44,23 @@ async function bmFetch(categoryFilter) {
     bmList = [];
   }
   bmSyncAccess();
-  bmRender(bmList);
+  bmApplyFilters();
   bmRefreshCategoryFilter(categoryFilter);
   if (typeof scheduleSpectrumDraw === "function") scheduleSpectrumDraw();
 }
 
+function bmApplyFilters() {
+  const text = (document.getElementById("bm-text-filter")?.value || "").trim().toLowerCase();
+  const filtered = text
+    ? bmList.filter((bm) =>
+        (bm.name || "").toLowerCase().includes(text) ||
+        (bm.category || "").toLowerCase().includes(text) ||
+        (bm.comment || "").toLowerCase().includes(text)
+      )
+    : bmList;
+  bmRender(filtered);
+}
+
 async function bmRefreshCategoryFilter(keepValue) {
   const sel = document.getElementById("bm-category-filter");
   if (!sel) return;
@@ -276,6 +288,11 @@ async function bmApply(bm) {
     bmFetch(e.target.value);
   });
 
+  // Text search filter (client-side, no re-fetch)
+  document.getElementById("bm-text-filter").addEventListener("input", () => {
+    bmApplyFilters();
+  });
+
   // Form submit
   document.getElementById("bm-form").addEventListener("submit", bmSave);