feat: channel name dropdown in Editor (Sprint 6 Part 5)

Two-row header: row 1 = existing controls, row 2 = channel ComboBox.
30 channel items grouped into Vocals/Drums/Bass/Keys/Synths/Strings/FX/Buses/Custom.
Custom... opens AlertWindow for free-text entry. Selection calls
processorRef.setChannelName() which updates registry + MCP.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Source/Plugin/PluginBridgeEditor.h

@@ -26,10 +26,11 @@ private:
     PluginBridgeProcessor& processorRef;
 
     // Top bar controls
-    juce::Label titleLabel;
-    juce::Label mcpStatusLabel;
-    juce::Label pluginStatusLabel;
+    juce::Label     titleLabel;
+    juce::Label     mcpStatusLabel;
+    juce::Label     pluginStatusLabel;
     juce::TextButton selectButton{"Select Plugin"};
+    juce::ComboBox  channelDropdown;
 
     // In-process plugin editor (null for unsafe plugins)
     std::unique_ptr<juce::AudioProcessorEditor> pluginEditor;
@@ -43,10 +44,12 @@ private:
     bool showingError      = false;
     bool audioOnlyMode     = false;
 
-    static constexpr int kTopBarHeight    = 32;
-    static constexpr int kAudioOnlyHeight = 80;
-    static constexpr int kDefaultWidth    = PluginPickerComponent::kWidth;
-    static constexpr int kDefaultHeight   = kTopBarHeight;
+    static constexpr int kTopBarHeight     = 32;
+    static constexpr int kChannelBarHeight = 26;
+    static constexpr int kHeaderHeight     = kTopBarHeight + kChannelBarHeight;
+    static constexpr int kAudioOnlyHeight  = 80;
+    static constexpr int kDefaultWidth     = PluginPickerComponent::kWidth;
+    static constexpr int kDefaultHeight    = kHeaderHeight;
 
     JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR(PluginBridgeEditor)
 };

Source/Plugin/PluginBridgeEditor.mm

@@ -50,6 +50,97 @@ PluginBridgeEditor::PluginBridgeEditor(PluginBridgeProcessor& p)
     selectButton.setColour(juce::ComboBox::outlineColourId,   juce::Colour(0xff404040));
     addAndMakeVisible(selectButton);
 
+    // ── Channel name dropdown ─────────────────────────────────────────────────
+    channelDropdown.addSectionHeading("── Vocals ──");
+    channelDropdown.addItem("Lead Vocal",     1);
+    channelDropdown.addItem("Backing Vocal",  2);
+    channelDropdown.addItem("Adlibs",         3);
+    channelDropdown.addSeparator();
+    channelDropdown.addSectionHeading("── Drums ──");
+    channelDropdown.addItem("Kick",           4);
+    channelDropdown.addItem("Snare",          5);
+    channelDropdown.addItem("Hi-Hat",         6);
+    channelDropdown.addItem("Overheads",      7);
+    channelDropdown.addItem("Percussion",     8);
+    channelDropdown.addSeparator();
+    channelDropdown.addSectionHeading("── Bass ──");
+    channelDropdown.addItem("Bass / 808",     9);
+    channelDropdown.addItem("Bass Guitar",    10);
+    channelDropdown.addItem("Sub Bass",       11);
+    channelDropdown.addItem("Synth Bass",     12);
+    channelDropdown.addSeparator();
+    channelDropdown.addSectionHeading("── Keys & Guitar ──");
+    channelDropdown.addItem("Piano / Keys",   13);
+    channelDropdown.addItem("Acoustic Guitar",14);
+    channelDropdown.addItem("Electric Guitar",15);
+    channelDropdown.addSeparator();
+    channelDropdown.addSectionHeading("── Synths ──");
+    channelDropdown.addItem("Synth Lead",     16);
+    channelDropdown.addItem("Synth Pad / Pluck", 17);
+    channelDropdown.addSeparator();
+    channelDropdown.addSectionHeading("── Strings & Brass ──");
+    channelDropdown.addItem("Strings",        18);
+    channelDropdown.addItem("Brass / Woodwind", 19);
+    channelDropdown.addItem("Orchestral",     20);
+    channelDropdown.addSeparator();
+    channelDropdown.addSectionHeading("── FX ──");
+    channelDropdown.addItem("Reverb / Delay", 21);
+    channelDropdown.addItem("Foley / Ambient",22);
+    channelDropdown.addSeparator();
+    channelDropdown.addSectionHeading("── Buses ──");
+    channelDropdown.addItem("Vocal Bus",      23);
+    channelDropdown.addItem("Drum Bus",       24);
+    channelDropdown.addItem("Guitar Bus",     25);
+    channelDropdown.addItem("Synth Bus",      26);
+    channelDropdown.addItem("Music Bus",      27);
+    channelDropdown.addItem("Instrument Bus", 28);
+    channelDropdown.addItem("Master Bus / Mix Bus", 29);
+    channelDropdown.addSeparator();
+    channelDropdown.addSectionHeading("── Custom ──");
+    channelDropdown.addItem("Custom...",      30);
+
+    channelDropdown.setColour(juce::ComboBox::backgroundColourId, juce::Colour(0xff2d2d2d));
+    channelDropdown.setColour(juce::ComboBox::textColourId,       kTextPrimary);
+    channelDropdown.setColour(juce::ComboBox::outlineColourId,    juce::Colour(0xff404040));
+    channelDropdown.setColour(juce::ComboBox::arrowColourId,      kTextSecondary);
+    channelDropdown.setTextWhenNothingSelected("Select channel...");
+
+    // Restore saved channel name
+    channelDropdown.setText(processorRef.getChannelName(), juce::dontSendNotification);
+
+    channelDropdown.onChange = [this]()
+    {
+        auto text = channelDropdown.getText();
+        if (text == "Custom...")
+        {
+            auto* aw = new juce::AlertWindow("Channel Name",
+                                             "Enter a name for this channel:",
+                                             juce::MessageBoxIconType::NoIcon);
+            aw->addTextEditor("name", processorRef.getChannelName());
+            aw->addButton("OK",     1);
+            aw->addButton("Cancel", 0);
+            aw->enterModalState(true,
+                juce::ModalCallbackFunction::create([this, aw](int result)
+                {
+                    if (result == 1)
+                    {
+                        auto name = aw->getTextEditorContents("name");
+                        if (name.isNotEmpty())
+                        {
+                            channelDropdown.setText(name, juce::dontSendNotification);
+                            processorRef.setChannelName(name);
+                        }
+                    }
+                    delete aw;
+                }), true);
+        }
+        else if (text.isNotEmpty())
+        {
+            processorRef.setChannelName(text);
+        }
+    };
+    addAndMakeVisible(channelDropdown);
+
     // ── Audio-only label ──────────────────────────────────────────────────────
     audioOnlyLabel.setFont(juce::FontOptions(11.0f));
     audioOnlyLabel.setJustificationType(juce::Justification::centred);
@@ -142,13 +233,13 @@ void PluginBridgeEditor::paint(juce::Graphics& g)
 {
     g.fillAll(kBgDark);
 
-    // Top bar
+    // Header (top bar + channel bar)
     g.setColour(kBgTopBar);
-    g.fillRect(getLocalBounds().removeFromTop(kTopBarHeight));
+    g.fillRect(getLocalBounds().removeFromTop(kHeaderHeight));
 
-    // Separator line under top bar
+    // Separator line under header
     g.setColour(juce::Colour(0xff333333));
-    g.fillRect(0, kTopBarHeight - 1, getWidth(), 1);
+    g.fillRect(0, kHeaderHeight - 1, getWidth(), 1);
 
     // Empty state hint (only when no picker, no plugin, no error)
     if (!activePicker && !pluginEditor && !audioOnlyMode
@@ -157,22 +248,26 @@ void PluginBridgeEditor::paint(juce::Graphics& g)
         g.setColour(juce::Colour(0xff444444));
         g.setFont(juce::FontOptions(12.0f));
         g.drawText("Click  Select Plugin  to browse your library",
-                   getLocalBounds().withTrimmedTop(kTopBarHeight),
+                   getLocalBounds().withTrimmedTop(kHeaderHeight),
                    juce::Justification::centred);
     }
 }
 
 void PluginBridgeEditor::resized()
 {
-    auto area   = getLocalBounds();
-    auto topBar = area.removeFromTop(kTopBarHeight).reduced(6, 4);
+    auto area = getLocalBounds();
 
+    // Row 1: title + select button + status + MCP port
+    auto topBar = area.removeFromTop(kTopBarHeight).reduced(6, 4);
     titleLabel.setBounds(topBar.removeFromLeft(80));
     selectButton.setBounds(topBar.removeFromLeft(110).reduced(0, 2));
     topBar.removeFromLeft(6);
     pluginStatusLabel.setBounds(topBar.removeFromLeft(topBar.getWidth() - 64));
     mcpStatusLabel.setBounds(topBar);
 
+    // Row 2: channel name dropdown (full width)
+    channelDropdown.setBounds(area.removeFromTop(kChannelBarHeight).reduced(6, 2));
+
     // Content area: picker > plugin editor > audio-only (priority order)
     if (activePicker)
         activePicker->setBounds(area);
@@ -299,7 +394,7 @@ void PluginBridgeEditor::showPluginMenu()
 
     // Resize editor to show the picker
     int newW = std::max(getWidth(),  PluginPickerComponent::kWidth);
-    int newH = kTopBarHeight + PluginPickerComponent::kHeight;
+    int newH = kHeaderHeight + PluginPickerComponent::kHeight;
     setSize(newW, newH);
 
     PBLOG("Editor", "showPluginMenu: picker opened");
@@ -318,12 +413,12 @@ void PluginBridgeEditor::hidePicker()
     {
         pluginEditor->setVisible(true);
         setSize(std::max(pluginEditor->getWidth(), kDefaultWidth),
-                pluginEditor->getHeight() + kTopBarHeight);
+                pluginEditor->getHeight() + kHeaderHeight);
     }
     else if (audioOnlyMode)
     {
         audioOnlyLabel.setVisible(true);
-        setSize(kDefaultWidth, kTopBarHeight + kAudioOnlyHeight);
+        setSize(kDefaultWidth, kHeaderHeight + kAudioOnlyHeight);
     }
     else
     {
@@ -358,7 +453,7 @@ void PluginBridgeEditor::attachPluginEditor()
 
     addAndMakeVisible(pluginEditor.get());
     int w = std::max(pluginEditor->getWidth(), kDefaultWidth);
-    int h = pluginEditor->getHeight() + kTopBarHeight;
+    int h = pluginEditor->getHeight() + kHeaderHeight;
     PBLOG("Editor", "attachPluginEditor: SUCCESS — size " + juce::String(w) + "x" + juce::String(h));
     setSize(w, h);
 }
@@ -387,7 +482,7 @@ void PluginBridgeEditor::showAudioOnlyUI()
                "Audio processing active. Use MCP or automation for parameters.",
         juce::dontSendNotification);
     audioOnlyLabel.setVisible(true);
-    setSize(kDefaultWidth, kTopBarHeight + kAudioOnlyHeight);
+    setSize(kDefaultWidth, kHeaderHeight + kAudioOnlyHeight);
 }
 
 void PluginBridgeEditor::hideAudioOnlyUI()