Generate JSON->event adapter via the events codemod

Extend build_events.py (the codemod) so events.json stays the source of
truth: each generated event class gains build_from_json(event), mapping a
pump-logs JSON event's eventProperties onto its {field}[Raw] attrs
(matched by normalized field name), plus RawEvent.build_from_json() which
derives timestampRaw from pumpDateTime so eventTimestamp/seqNum/eventId
keep working. Add generic.Event_from_json()/Events_from_json() dispatchers
mirroring Event()/Events(); unknown eventCode -> bare RawEvent.

Enum/dictionary/ratio fields are raw ints (map directly onto {field}Raw so
existing properties resolve); bitmask fields arrive as arrays of set-bit
indices, converted to the raw int via _bitmask_arr_to_int. events.py is
regenerated; the byte-path build() is unchanged.

Tests: tests/eventparser/test_from_json.py.

tests/eventparser/test_from_json.py

@@ -0,0 +1,91 @@
+#!/usr/bin/env python3
+
+import unittest
+
+from tconnectsync.eventparser.generic import Event_from_json, Events_from_json
+from tconnectsync.eventparser import events as eventtypes
+from tconnectsync.eventparser.raw_event import RawEvent
+
+# Trimmed real pump-log events (values from a captured account response).
+BASAL_279 = {
+    "deviceAssignmentId": "4ff6bebc-d4d6-4423-b123-eecfcf5a4238",
+    "eventCode": 279,
+    "sequenceGroup": 0,
+    "sequenceNumber": 393131,
+    "pumpDateTime": "2026-04-30T00:03:29",
+    "eventProperties": {
+        "commandedRateSource": 3, "reservedA2": 0, "spareA3": 0,
+        "commandedRate": 0, "profileBasalRate": 1000, "algorithmRate": 0,
+        "tempRate": 65535,
+    },
+    "estimatedDateTime": "2026-04-30T00:03:29Z",
+}
+
+ALARM_5 = {
+    "deviceAssignmentId": "4ff6bebc-d4d6-4423-b123-eecfcf5a4238",
+    "eventCode": 5,
+    "sequenceGroup": 0,
+    "sequenceNumber": 500001,
+    "pumpDateTime": "2026-04-30T01:00:00",
+    "eventProperties": {"alarmId": 18, "faultLocatorData": 8311, "param1": 3993668, "param2": 0},
+    "estimatedDateTime": "2026-04-30T01:00:00Z",
+}
+
+
+class TestBuildFromJson(unittest.TestCase):
+    maxDiff = None
+
+    def test_dispatches_to_correct_class(self):
+        self.assertIsInstance(Event_from_json(BASAL_279), eventtypes.LidBasalDelivery)
+        self.assertIsInstance(Event_from_json(ALARM_5), eventtypes.LidAlarmActivated)
+
+    def test_plain_fields(self):
+        ev = Event_from_json(BASAL_279)
+        self.assertEqual(ev.commandedRate, 0)
+        self.assertEqual(ev.profileBasalRate, 1000)
+        self.assertEqual(ev.tempRate, 65535)
+
+    def test_envelope_fields(self):
+        ev = Event_from_json(BASAL_279)
+        self.assertEqual(ev.seqNum, 393131)
+        self.assertEqual(ev.eventId, 279)
+
+    def test_timestamp_preserves_wall_clock(self):
+        # eventTimestamp keeps pumpDateTime's wall-clock (tz forced to the
+        # configured TIMEZONE_NAME), so the naive portion round-trips exactly.
+        ev = Event_from_json(BASAL_279)
+        self.assertEqual(ev.eventTimestamp.format('YYYY-MM-DDTHH:mm:ss'), "2026-04-30T00:03:29")
+
+    def test_missing_plain_field_defaults_to_none(self):
+        event = dict(BASAL_279)
+        event["eventProperties"] = {k: v for k, v in BASAL_279["eventProperties"].items() if k != "tempRate"}
+        ev = Event_from_json(event)
+        self.assertIsNone(ev.tempRate)
+        self.assertEqual(ev.commandedRate, 0)  # others still parse
+
+    def test_extra_keys_are_ignored(self):
+        event = dict(BASAL_279)
+        event["eventProperties"] = dict(BASAL_279["eventProperties"], someFutureField=42)
+        ev = Event_from_json(event)  # must not raise
+        self.assertFalse(hasattr(ev, "someFutureField"))
+
+    def test_events_from_json_yields_in_order(self):
+        out = list(Events_from_json([BASAL_279, ALARM_5]))
+        self.assertEqual([type(e).__name__ for e in out],
+                         ["LidBasalDelivery", "LidAlarmActivated"])
+
+    def test_unknown_eventcode_falls_back_to_rawevent(self):
+        ev = Event_from_json({
+            "eventCode": 99999,
+            "sequenceNumber": 7,
+            "pumpDateTime": "2026-04-30T00:00:00",
+            "eventProperties": {},
+        })
+        self.assertIs(type(ev), RawEvent)
+        self.assertEqual(ev.eventId, 99999)
+        self.assertEqual(ev.seqNum, 7)
+        self.assertEqual(ev.eventTimestamp.format('YYYY-MM-DDTHH:mm:ss'), "2026-04-30T00:00:00")
+
+
+if __name__ == "__main__":
+    unittest.main()