tr_config: logColor is a string in TR 5.x; TR_CENTER_HZ keeps the control channels it covers (node-26#45)

Both found on node-002. A boolean logColor made TR 5.2.1 refuse the whole
config (json type_error.302). MTA Zone 2's live control channel is 770.43 MHz,
outside the widest-cover window, so a centre override must be able to pick
which control channels to keep rather than demand all of them fit.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

drb-edge-node/tests/test_trunk_recorder.py

@@ -499,3 +499,10 @@ def test_wide_control_channel_list_is_cut_to_what_one_sdr_covers():
     # MTA Zone 2 (node-002): five control channels spanning 4.15 MHz.
     ccs = [770_156_250, 770_431_250, 773_293_750, 773_843_750, 774_306_250]
     assert tr_config.widest_cover(ccs, 2_400_000) == ccs[2:]
+
+
+def test_center_override_keeps_only_the_control_channels_it_covers():
+    tr, _ = tr_config.build_tr_config(
+        "P25", "MTA", {"control_channels": [770.15625, 770.43125, 773.29375]},
+        **{**TR_KW, "center_override": 770_900_000})
+    assert tr["systems"][0]["control_channels"] == [770_156_250, 770_431_250]