Merge Examples/RL tabs into single unified toolbar across all four UIs.
Users can now freely mix supervised learning (Add Example + Train) with
RL feedback (thumbs up/down) without switching modes. Param bar dragging
is always enabled.
Add Web MIDI input module (js/synth/midi-input.js) for external MIDI
controllers — routes note on/off to C15 synth, CC 1/2 to joystick.
Add gamepad module (js/ui/gamepad.js) with auto-detection, deadzone,
and axis normalization across all UIs.
Fix synth parameter sync: routeOutputs() now called after trainModel()
in onThumbsUp and loadState to prevent stale params on first joystick
move. Add separate Clear Examples button (dataset only, keeps weights).
