Rework channel labeling and add source picker to virtual-channel creation

Relabel every channel picker/header to "NAME (DEVICE/SIGNAL)" instead of
the previous "DEVICE/SIGNAL (NAME)" ordering, consistently across
channels_window.py (_channel_combo, ChannelPickerDialog,
ChannelPipelineBlock header), plot_builder.py, plot_config.py,
control_editor.py, and plot_window.py.

While touching each of those pickers, added the missing `.enabled`
filter that _make_picker()/_x_cb/_build_channel_picker lacked (the
default-layout builders already filtered disabled channels; these
manual "add channel to pane" pickers didn't).

Devices window Signals tab: removed the separate "Signal ID" column
(folded into the existing non-editable Device column instead of the
editable Name column, to avoid corrupting the in-place channel rename
feature that column already supports).

Channels window Virtual Channels pane: added a "Source" dropdown next
to "+ Add Channel" — picking a source pre-seeds the new derived
channel with it via DerivedBlock._add_src(); leaving it on the default
"none" entry keeps today's behavior of creating an empty channel.

Note: docs/ToDo.md's "Channels window UI" items referred to the *live*
UI (this window's PipelineTab + the Devices window's Signals tab), not
SignalsListTab in this same file, which its own module docstring flags
as dead/unused code kept only for old-profile compatibility — verified
by grepping for any instantiation of it (none exist).

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

1 files changed, 12 insertions, 4 deletions

diff --git a/ui/windows/plot_window.py b/ui/windows/plot_window.py
index 9edf046..f311e9e 100644
--- a/ui/windows/plot_window.py
+++ b/ui/windows/plot_window.py
@@ -355,10 +355,14 @@ class PaneBlock(QFrame):
         self._x_cb.addItem("⏱  Time (elapsed s)", userData="time")
         for dev in self.registry.all_instances():
             for ch in dev.info.channels:
-                self._x_cb.addItem(f"{dev.info.device_id}/{ch.channel_id}  ({ch.name})",
+                if not ch.enabled:
+                    continue
+                self._x_cb.addItem(f"{ch.name}  ({dev.info.device_id}/{ch.channel_id})",
                                    userData=f"{dev.info.device_id}/{ch.channel_id}")
         for dc in self.processor.get_derived():
-            self._x_cb.addItem(f"[virtual] {dc.channel_id}",
+            if not dc.enabled:
+                continue
+            self._x_cb.addItem(f"{dc.name}  ([virtual]/{dc.channel_id})",
                                userData=f"derived/{dc.channel_id}")
         for i in range(self._x_cb.count()):
             if self._x_cb.itemData(i) == self.spec.x_source:
@@ -417,10 +421,14 @@ class PaneBlock(QFrame):
         cb = QComboBox(); cb.setObjectName("channelPickerCb")
         for dev in self.registry.all_instances():
             for ch in dev.info.channels:
-                cb.addItem(f"{dev.info.device_id} / {ch.channel_id}  ({ch.name})",
+                if not ch.enabled:
+                    continue
+                cb.addItem(f"{ch.name}  ({dev.info.device_id}/{ch.channel_id})",
                            userData=(dev.info.device_id, ch.channel_id, ch.name, ch.color))
         for dc in self.processor.get_derived():
-            cb.addItem(f"[virtual] {dc.channel_id}  ({dc.name})",
+            if not dc.enabled:
+                continue
+            cb.addItem(f"{dc.name}  ([virtual]/{dc.channel_id})",
                        userData=("derived", dc.channel_id, dc.name, dc.color))
         return cb