docs: help/README catch up with v3.8.0; keyset-number wording; RU "пресет"

Documentation:
- help (§1/§3): the SCP80 tab is switched by three pills - the tab list and the
  section intro now name the TAR probe (RU "TAR-сканер"); §3.1/§3.2 describe the
  Keyset selector next to the preset selector (and that a successful PoR
  advances the counter only when SPI1 carries a counter check); §4 describes
  the keyset editor rows, the derived number and the per-keyset counters; the
  probe section keeps its counter rule.
- README/README_RUS: the SCP80 tab says three pills and gains a "TAR probe" /
  "TAR-сканер" section (standard list, verdicts, counter persistence); the
  Cards section is rewritten for the server-side store - keysets, server-owned
  per-keyset counters with the audit trail, JSON export/import as the migration
  path, the keyset editor, the equipped-card mismatch banner - and the field
  table, "Add a card" and "Edit / remove" follow.

Terminology:
- "key version" is no longer used for SCP80 keysets in the UI, the server error
  strings and the docs: the selector is "Keyset", its options "Keyset 1 - ...",
  the messages say "keyset N ...".  The TS 102 225 A.1/A.2 quotes and the GP
  PUT KEY P1 field keep the spec's own wording.
- RU keeps the word "keyset" untranslated ('Добавить keyset', 'Номер keyset',
  "не является keyset пресета", ...) and uses "пресет" instead of
  "предустановка" throughout the dictionary, the help and README_RUS.

sw cache simple-v340.  Tests: 742 Node / 619 Python.

tests/test_fetch_routes.py

@@ -613,7 +613,7 @@ class PresetStoreHttpTests(unittest.TestCase):
             'sp': '00', 'spi1': '16', 'spi2': '01', 'kic': '15', 'kid': '25',
             'tar': '000000', 'cntr': '0000000001'})
         self.assertEqual(status, 400, resp)
-        self.assertIn('same key version', resp['error'])
+        self.assertIn('same keyset number', resp['error'])
 
     def test_send_ota_refuses_an_undefined_key_version(self):
         p = self.store.add(self._preset(iccid='8970119000004600098'))
@@ -622,7 +622,7 @@ class PresetStoreHttpTests(unittest.TestCase):
             'sp': '00', 'spi1': '16', 'spi2': '01', 'kic': '35', 'kid': '35',
             'tar': '000000', 'cntr': '0000000001', 'preset_id': p['id']})
         self.assertEqual(status, 400, resp)
-        self.assertIn('key version 3 is not defined', resp['error'])
+        self.assertIn('keyset 3 is not defined', resp['error'])
 
     def test_the_counter_lands_in_the_keyset_of_the_packet(self):
         p = self.store.add(self._preset(keysets=[
@@ -659,7 +659,7 @@ class PresetStoreHttpTests(unittest.TestCase):
         status, resp = self._post('/api/ram-install', {
             'cap_hex': _mini_cap_hex(), 'kic': '35', 'kid': '35', 'preset_id': p['id']})
         self.assertEqual(status, 400, resp)
-        self.assertIn('key version 3 is not defined', resp['error'])
+        self.assertIn('keyset 3 is not defined', resp['error'])
 
     def test_a_keyless_send_leaves_every_counter_untouched(self):
         # SPI1 00: the counter is "present, ignored, never updated"