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_presets.py

@@ -3,7 +3,7 @@
 The store replaces the localStorage presets; the ICCID normalisation must stay
 byte-compatible with the PWA's `cardsNormIccid` (digits / spaced / raw
 nibble-swapped EF hex), every keyset carries its own monotonic counter (one per
-key version, TS 102 225 Annex A.1), and the file must survive a corrupt store
+keyset number, TS 102 225 Annex A.1), and the file must survive a corrupt store
 without silently destroying it.
 """
 
@@ -122,7 +122,7 @@ class StoreCrudTests(unittest.TestCase):
         # TS 102 225 A.2: a mismatch is rejected by the card - refuse it here
         with self.assertRaises(presets.PresetError) as ctx:
             self.store.add(preset(keysets=[keyset(kic='15', kid='25')]))
-        self.assertIn('same key version', str(ctx.exception))
+        self.assertIn('same keyset number', str(ctx.exception))
 
     def test_key_version_00_and_duplicates_are_refused(self):
         with self.assertRaises(presets.PresetError) as ctx:
@@ -131,7 +131,7 @@ class StoreCrudTests(unittest.TestCase):
         with self.assertRaises(presets.PresetError) as ctx:
             self.store.add(preset(keysets=[keyset(kic='15', kid='15'),
                                            keyset(kic='15', kid='15')]))
-        self.assertIn('duplicate key version', str(ctx.exception))
+        self.assertIn('duplicate keyset number', str(ctx.exception))
         # the byte must be a full hex byte
         with self.assertRaises(presets.PresetError):
             self.store.add(preset(keysets=[keyset(kic='1', kid='1')]))
@@ -237,7 +237,7 @@ class StoreCounterTests(unittest.TestCase):
         self.assertEqual(self.counter(), '0000000005')
 
     def test_each_key_version_has_its_own_counter(self):
-        # TS 102 225 A.1: a dedicated counter per key version
+        # TS 102 225 A.1: a dedicated counter per keyset
         p = self.store.update(self.p['id'], {'keysets': [
             keyset(kic='15', kid='15', cntr='0000000002'),
             keyset(kic='29', kid='29', cntr='0000000007')]})