v3.22.0 (review fixes): the quota zero, the suite repair paths, the docs

Second review round on the unpushed v3.20.0-v3.22.0 batch:

- install parameters: a zero memory quota (nv_quota: 0 - the vendor
  reference form's C7 02 0000 C8 02 0000) is composed instead of being
  dropped as "unset" (only None/blank leaves the TLV out); a truncated EF
  length in stk_params is refused instead of read as an empty EF.
- test suites: a suite whose member script is gone is repairable - the
  update endpoint accepts pruning a dangling reference (a removal of a
  live script stays refused; the PWA's row Delete prunes it), and
  reconcile_scripts_to_suites() lists an orphan even when its suite_id
  write is refused by the validator, so a stored script that no longer
  validates stays visible in the editor and fails at run start with the
  message instead of disappearing.
- engine/PWA: the proactive action refuses a check.data (its result data
  is the drained-command list - the check was silently ignored); the
  vestigial _testScriptDraft is gone; berLenStr emits the 2/3-byte BER
  long form (a >255-byte C9 composes correctly).
- docs: api.md (the stop cleanup answers ok, never an automatic cancel;
  the server persists the counters - the PWA does not write them back; the
  suite bundle import always merges the scripts; the quota-0 note) and
  test-scripts.md (the event action covers all modelled events; the
  direct-create path needs a suite_id; the format history); help EN/RU
  counter wording.
- tests: the zero quota / truncated EF, the prune path, the invalid-script
  listing, the proactive data-check refusal, berLenStr and the >255-byte
  C9.  Tests: 839 frontend + 804 Python; sw cache simple-v403.

tests/test_ota_helpers.py

@@ -1612,6 +1612,30 @@ class CapApduSequenceTest(unittest.TestCase):
         self.assertEqual(_compose_install_params('C900EF04C7020064', 'EA0480000000'),
                          'C900EF04C7020064EA0480000000')
 
+    def test_install_params_zero_quota_and_truncated_ef(self):
+        # `0` is a valid quota (the vendor reference form carried
+        # `C7 02 0000 C8 02 0000`): only an absent/empty field is unset.
+        from pysim_simple_server.server import (_compose_install_params,
+                                                _single_ef_value)
+        self.assertEqual(_compose_install_params('', '', nv_quota=0),
+                         'C900EF04C8020000')
+        self.assertEqual(_compose_install_params('', '', volatile_quota=0,
+                                                 nv_quota=0),
+                         'C900EF08C7020000C8020000')
+        self.assertEqual(_compose_install_params('', '', nv_quota='0'),
+                         'C900EF04C8020000')
+        self.assertEqual(_compose_install_params('', '', nv_quota=0.0),
+                         'C900EF04C8020000')
+        # an absent/empty field is not composed
+        self.assertEqual(_compose_install_params('', '', nv_quota='',
+                                                 volatile_quota=None), 'C900')
+        # a truncated EF length is malformed, not an empty EF
+        for bad in ('EF', 'EF81', 'EF80', 'EF8201'):
+            with self.assertRaises(ValueError, msg=bad):
+                _single_ef_value(bad)
+        # an empty EF (EF 00) is legal
+        self.assertEqual(_single_ef_value('EF00'), '')
+
     def test_install_apdu_carries_the_composed_parameters(self):
         from pysim_simple_server.server import _cap_install_apdu
         # CA-form STK + quotas: `C9 00 EF{C7,C8,CA}` - one EF (the form the