Hide proprietary efficiency score from frontend

Discontinue surfacing the calculated efficiency score (A–F grade +
0–100 value) to users, while keeping all stored data and admin tooling
intact so the change is fully reversible.

Frontend display removed:
- Tire card efficiency badge (cards.js); the Roamer real-world mi/kWh
  pill, which shared the same styling, is preserved and un-nested so it
  renders on its own.
- Compare page efficiency badge in tire headers and the Performance
  section, plus its now-dead CSS and best-value highlighting.
- "Efficiency Grade" option in the sort dropdown.
- Orphaned "Efficiency Score" tooltip.

Default sort moved off efficiency to "Real-World Efficiency" so results
are no longer ordered by the discontinued score:
- Client sort + allow-list (filters.js, validation.js).
- Server-side pagination mode (server.js + AJAX handler).
- Public REST /tires endpoint. efficiency_score is kept as an accepted
  sort value for backward compatibility, just not the default.

Deliberately untouched: DB columns, calculation engine, admin tire-edit
preview / "Recalculate Grades", CSV import/export, and the efficiency
calc endpoints. Values still flow through the payload at their existing
array positions; the frontend just no longer renders or sorts on them.

Build regenerated (all 7 targets); 83/83 JS tests pass.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Author: RivianTrackr

frontend/js/compare.js

@@ -67,11 +67,6 @@ const COL = {
   roamerEfficiency: 24, roamerTotalKm: 25, roamerVehicleCount: 26, roamerVehicleBreakdown: 27
 };
 
-// --- Efficiency badge colors ---
-const GRADE_COLORS = {
-  A: "#34c759", B: "#7dc734", C: "#facc15", D: "#f97316", F: "#b91c1c"
-};
-
 // --- Determine "best" values for highlighting ---
 function findBestValues(tires) {
   const best = {};
@@ -86,26 +81,12 @@ function findBestValues(tires) {
   const warranties = tires.map(t => parseInt(t[COL.warranty])).filter(n => !isNaN(n) && n > 0);
   if (warranties.length > 1) best.warranty = Math.max(...warranties);
 
-  const scores = tires.map(t => parseInt(t[COL.effScore])).filter(n => !isNaN(n) && n > 0);
-  if (scores.length > 1) best.effScore = Math.max(...scores);
-
   const roamerVals = tires.map(t => parseFloat(t[COL.roamerEfficiency])).filter(n => !isNaN(n) && n > 0);
   if (roamerVals.length > 1) best.roamerEfficiency = Math.max(...roamerVals);
 
   return best;
 }
 
-// --- Build efficiency badge HTML ---
-function effBadge(score, grade) {
-  const s = escapeHTML(score || "-");
-  const g = escapeHTML((grade || "-").toUpperCase());
-  const color = GRADE_COLORS[g] || "#a19e97";
-  return `<span class="cmp-eff-badge">
-    <span class="cmp-eff-grade" style="background:${color}">${g}</span>
-    <span class="cmp-eff-score">${s}/100</span>
-  </span>`;
-}
-
 // --- Build tag HTML ---
 function renderTags(tagStr) {
   if (!tagStr || tagStr === "-") return "-";
@@ -217,10 +198,6 @@ function renderComparison(rows, indexes) {
             <span class="cmp-tire-meta-label">Weight</span>
             <span class="cmp-tire-meta-value">${fmtWeight(t[COL.weight])}</span>
           </div>
-          <div class="cmp-tire-meta-item">
-            <span class="cmp-tire-meta-label">Efficiency</span>
-            <span class="cmp-tire-meta-value">${effBadge(t[COL.effScore], t[COL.effGrade])}</span>
-          </div>
         </div>
       </div>
     </div>`;
@@ -239,7 +216,6 @@ function renderComparison(rows, indexes) {
   ], tires, best, n);
 
   html += specSection('gauge-high', 'Performance', [
-    ['Efficiency', t => effBadge(t[COL.effScore], t[COL.effGrade]), 'effScore'],
     ['Real-World Efficiency', t => {
       const v = parseFloat(t[COL.roamerEfficiency]);
       if (!v || v === 0) return '-';