Order scan lists by discovery time, not RSSI, so they stay still

bc_snapshot re-sorted by RSSI every refresh, so entries jumped around as
signal fluctuated. Sort by first-seen instead: the list is stable and new
devices append at the bottom. Applies to every app that uses the shared
snapshot (BT Inspector, HID Host, Sensor Dashboard, GATT Fuzzer).

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01LEaD4ZeAfvWLBUxXp8G11r

libble/ble_central.c

@@ -351,10 +351,12 @@ size_t bc_snapshot(BleCentral* bc, BcDevice* out, size_t max) {
         d->logged = true;
     }
     furi_mutex_release(bc->mutex);
-    for(size_t i = 1; i < n; i++) { // insertion sort by RSSI, strongest first (n <= 32)
+    // Order by discovery time (first seen) so the list is stable and doesn't
+    // jump around as RSSI changes. Insertion sort, n <= 32.
+    for(size_t i = 1; i < n; i++) {
         BcDevice d = out[i];
         size_t j = i;
-        while(j > 0 && out[j - 1].rssi < d.rssi) {
+        while(j > 0 && out[j - 1].first_seen > d.first_seen) {
             out[j] = out[j - 1];
             j--;
         }