Fix piano roll not updating after pitch bend node value change

[alexandra-russell]

Summary

Fixes #7675. When double-clicking a pitch bend node in the Automation Editor to change its value, the Piano Roll did not update until the cursor hovered over it.

Root cause

fineTuneValue() changes node values directly via AutomationNode::setInValue() / setOutValue(). Those methods recalculate tangents but do not emit dataChanged(). The Piano Roll's repaint is wired to AutomationClip::dataChanged() (connected when the detuning curve is created), so it never received a signal to redraw.

By contrast, dragging nodes goes through AutomationClip::putValue(), which does emit dataChanged() -- this is why dragging works but double-click did not.

Fix

Emit dataChanged() on the clip at the end of fineTuneValue(), after the node value is set. AutomationEditor is already a declared friend of AutomationClip, so it has access to the protected signal.

Test plan

• Open a new project and create a MIDI clip
• Place a note in the Piano Roll and enter pitch bend mode (Shift+T)
• Click the note to create a detuning curve, add a couple of nodes
• Shift-click the note to open the Automation Editor
• Double-click a node and enter a new value
• Verify the Piano Roll pitch bend line updates immediately without needing to hover

[regulus79]

I haven't tested, but the fix looks fine. It seems that when normally editing an automation clip, AutomationClip::setDragValue which called AutomationClip::putValue calls emit dataChanged(), but here when double-clicking and entering a value, it directly edits the value of that node, bypassing those functions, which means dataChanged is never emitted.

[extern-stat]

Can you reproduce the bug this fixes (#7675) on the latest nightly? I tried reproducing it, but the piano roll updated correctly even when double clicking in the automation editor. It looks like AutomationEditor's mouseDoubleClickEvent() calls update() after calling fineTuneValue(), which then calls PianoRoll's update() function directly when note detuning.