fix: DELETE APDU is case 3 - no phantom command (v3.6.15)

The Explore delete showed "Failed: por_ok - remote SW 6700" while the delete
executed: ramDeleteApdu appended the trailing Le, and this card's SCP80
layer counts a trailing byte as a phantom second command whose SW 6700
masked the real result (count=2, last SW 6700) - the same quirk as
INSTALL [for load] before v3.6.8.

- ramDeleteApdu and the chain builder's DELETE row emit the case-3 APDU
  (4F AID TLV, no Le); the SCP81 Delete-AID template follows (it reuses
  ramDeleteApdu).
- tests updated (delete APDU expectations in ram/ram_counter_flow/scripts).

641 frontend / 496 Python green; version 3.6.15; sw simple-v288.

frontend/sw.js

@@ -1,4 +1,4 @@
-const CACHE = 'simple-v287';
+const CACHE = 'simple-v288';
 const URLS = [
   'index.html',
   'help.html',