v3.12.0: the card preset carries the card's CAT (USAT) release

The release selector lives in the preset rather than a global chip: presets
already travel with the card (ICCID auto-selection, export/import), and the
operations that will consume the release are preset-aware.

- presets.py: the optional `release` field (4-18; empty = unspecified) joins
  PRESET_FIELDS; a value outside 4-18 is refused on save/import; the store
  schema version is 5.
- catrelease.py: DEFAULT_RELEASE = 12 and preset_release() - the effective
  release is the preset's own value, else Rel-12 (the safe level for cards
  whose release is not known; an unset release never filters anything away).
  The PWA mirrors both (CAT_RELEASE_DEFAULT + presetRelease()), drift-guarded.
- Cards tab: the editor's header row gains a compact CAT release select
  (unspecified / pre-Rel-6 stored as 5 / Rel-6 ... Rel-18); the empty option
  names the Rel-12 default and the tooltip explains the guard; the field is
  collected, cleared and restored with the other form fields.
- Nothing filters yet: the Simulator's event parameters (stage 3) will use
  the effective release.
- docs/api.md + help EN/RU updated; sw cache simple-v368.

tests/test_presets.py

@@ -234,6 +234,21 @@ class StoreCrudTests(unittest.TestCase):
         self.assertEqual(p['pin1'], '1234')
         self.assertEqual(p['puk1'], '12345678')
 
+    def test_release_is_optional_and_must_be_4_to_18(self):
+        p = self.store.add(preset())
+        self.assertEqual(p['release'], '')
+        p = self.store.add(preset(name='Rel', release='14'))
+        self.assertEqual(p['release'], '14')
+        # numbers arrive as strings from the form and as ints from the API
+        p = self.store.add(preset(name='Int', release=4))
+        self.assertEqual(p['release'], '4')
+        p = self.store.add(preset(name='Top', release=' 18 '))
+        self.assertEqual(p['release'], '18')
+        for bad in ('3', '19', '0', '20', 'abc', '1x', '012'):
+            with self.assertRaises(presets.PresetError) as ctx:
+                self.store.add(preset(name='X', release=bad))
+            self.assertIn('release', str(ctx.exception))
+
     def test_duplicate_iccid_is_refused_across_stored_forms(self):
         self.store.add(preset(iccid=DIGITS))
         with self.assertRaises(presets.PresetError) as ctx: