[fix](trx-rs): don't use fabricated TLEs for satellite pass predictions

Hardcoded fallback TLEs had approximate orbital elements (round numbers for RAAN, arg of perigee, mean anomaly) producing pass times hours off. Return empty predictions with a clear error when CelesTrak data is not yet available. Add TLE source and satellite count to the API response.

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

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

@@ -292,6 +292,7 @@ document
 let satPredData = [];
 let satPredFilterText = "";
 let satPredMinEl = 0;
+let satPredSatCount = 0;
 const satPredFilterInput = document.getElementById("sat-pred-filter");
 const satPredMinElSelect = document.getElementById("sat-pred-min-el");
 
@@ -375,7 +376,11 @@ function renderSatPredictions(passes, error) {
     fragment.appendChild(row);
   }
   list.replaceChildren(fragment);
-  if (status) status.textContent = `${passes.length} pass${passes.length === 1 ? "" : "es"} in the next 24 h · times in UTC`;
+  if (status) {
+    let text = `${passes.length} pass${passes.length === 1 ? "" : "es"} in the next 24 h · times in UTC`;
+    if (satPredSatCount > 0) text += ` · ${satPredSatCount} satellites tracked`;
+    status.textContent = text;
+  }
 }
 
 async function loadSatPredictions() {
@@ -387,6 +392,7 @@ async function loadSatPredictions() {
     const resp = await fetch("/sat_passes");
     if (!resp.ok) throw new Error(`HTTP ${resp.status}`);
     const data = await resp.json();
+    satPredSatCount = data.satellite_count || 0;
     if (data.error) {
       satPredData = [];
       renderSatPredictions([], data.error);