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, 15 insertions, 5 deletions

diff --git a/ui/windows/channels_window.py b/ui/windows/channels_window.py
index 381800a..38d477b 100644
--- a/ui/windows/channels_window.py
+++ b/ui/windows/channels_window.py
@@ -74,7 +74,7 @@ def _channel_combo(registry: DeviceRegistry,
         for ch in dev.info.channels:
             if not ch.enabled:
                 continue
-            label = f"{dev.info.device_id} / {ch.channel_id}  ({ch.name})"
+            label = f"{ch.name}  ({dev.info.device_id}/{ch.channel_id})"
             if show_unit and ch.unit:
                 label += f"  [{ch.unit}]"
             cb.addItem(label, userData=(dev.info.device_id, ch.channel_id))
@@ -115,7 +115,7 @@ class ChannelPickerDialog(QDialog):
                 if (dev.info.device_id, ch.channel_id) in already_shown:
                     continue
                 any_available = True
-                label = f"{dev.info.device_id} / {ch.channel_id}  ({ch.name})"
+                label = f"{ch.name}  ({dev.info.device_id}/{ch.channel_id})"
                 if ch.unit:
                     label += f"  [{ch.unit}]"
                 chk = QCheckBox(label)
@@ -236,7 +236,7 @@ class ChannelPipelineBlock(QFrame):
         # Header
         hdr = QWidget(); hdr.setObjectName("plotBlockHeader"); hdr.setFixedHeight(32)
         hl  = QHBoxLayout(hdr); hl.setContentsMargins(8, 0, 6, 0)
-        title = f"{self.dev_id} / {self.ch_id}  ({ch_name})"
+        title = f"{ch_name}  ({self.dev_id}/{self.ch_id})"
         if unit:
             title += f"  [{unit}]"
         self._title_lbl = QLabel(title); self._title_lbl.setObjectName("traceSource")
@@ -307,7 +307,7 @@ class ChannelPipelineBlock(QFrame):
         self._body.setVisible(False)
 
     def _refresh_title(self):
-        title = f"{self.dev_id} / {self.ch_id}  ({self._ch_name})"
+        title = f"{self._ch_name}  ({self.dev_id}/{self.ch_id})"
         if self._unit:
             title += f"  [{self._unit}]"
         self._title_lbl.setText(title)
@@ -444,7 +444,12 @@ class PipelineTab(QWidget):
         virt_bar = QWidget(); virt_bar.setObjectName("cfgGlobalBar")
         vb_lay = QHBoxLayout(virt_bar); vb_lay.setContentsMargins(10, 7, 10, 7); vb_lay.setSpacing(6)
         vb_lbl = QLabel("Channels"); vb_lbl.setObjectName("devWindowTitle")
-        vb_lay.addWidget(vb_lbl, 1)
+        vb_lay.addWidget(vb_lbl)
+        self._src_cb = _channel_combo(self.registry, self.processor, include_derived=True)
+        self._src_cb.setObjectName("channelPickerCb")
+        self._src_cb.insertItem(0, "Source: none (empty channel)", userData=None)
+        self._src_cb.setCurrentIndex(0)
+        vb_lay.addWidget(self._src_cb, 1)
         add_virt = QPushButton("＋ Add Channel"); add_virt.setObjectName("addTraceBtn")
         add_virt.clicked.connect(self._add_virtual)
         vb_lay.addWidget(add_virt)
@@ -579,6 +584,11 @@ class PipelineTab(QWidget):
                             kind="expression", color=color)
         blk = self._make_derived_block(dc)
         self._virt_inner.insertWidget(self._virt_inner.count() - 1, blk)
+        # Pre-seed the source picked in the bar above, if any — otherwise the
+        # channel is created empty and sources can be added manually.
+        src = self._src_cb.currentData()
+        if src:
+            blk._add_src(src)
 
     def _make_derived_block(self, dc: DerivedChannel) -> DerivedBlock:
         blk = DerivedBlock(dc, self.registry, self.processor)