Pre- and post-fader realtime effects

### Your idea

Real-time effects in the track's effect panel may be ordered, but Track Pan and Track Gain are always after other real-time effects.

This proposal is to allow Track Pan and Track Gain to be moved with respect to other real-time effects. One possible implementation might be to add place-holders in the left Effect panel that are aliases for the Track Pan and Track Gain effect, so that their position in the real-time effect chain is both obvious and adjustable.

### Problem to be solved

The order in which effects are applied may be important. For example, if a limiter is applied before Track Gain, the effect will be different from applying (non-unity) track gain before a limiter.

Currently, real-time effects in the left panel are applied first to the selected audio, then the Track Pan and Gain are applied. This can have surprising consequences.

Example:
A hard clipping effect may be set to clip at -6dB. A user may reasonably expect that reducing the track level (Track Gain) will reduce the amount of clipping, but this does not occur because the clipping effect is applied before the track gain.

On the other hand, a reverb effect would normally be placed before track gain so that it retains the same wet/dry mix when adjusting the level.

### Prior art

Mixing consoles generally allow effects to be placed pre / post level and pan.

### Additional context

_No response_

The issue names no files, tests, or entry points. Start by tracing how the track effect panel orders realtime effects and where Track Pan and Track Gain are applied. Done means users can place those controls before or after other realtime effects, with the resulting gain, clipping, and reverb behavior matching the selected order.

Written by the indexing model from the issue text.