TREE_TIME_XY Chart ignoring most API content and is not drawn properly time synced (line mode)

### Bug Description:

The chart type `TREE_TIME_XY` is not properly timestamp synced (in line mode).
All provided `xValues` are ignored which breaks the drawing for non-periodic data series. Still the drawing is panned synchronized to the overview and other time-based graphs. The time-based cursor position is misleading as well. This give a very bad user experience and feels like a bug.

The API offers multiple types of data for the x axis (`xRanges`, `xCategories`) and some meta data in `xValuesDescription`. All of these are ignored by the current implementation.

There is a second type of chart `TREE_GENERIC_XY` which behaves similar. From API point of view it is unclear which of both to use for what type of graphs. E.g., we are trying to plot time-based analog and digital data series.

### Steps to Reproduce:

1. Serve non-periodic time-based data series on `/experiments/:expUUID/outputs/XY/:outputId/xy` endpoint
2. Observe time-base mismatch in XY Graph window on cursor and zoom

### Additional Information

- Operating System: MacOS 26
- VSCode Version: 1.117.0