Fix Overpass Mono variable interpolation

[devs6186]

Summary

• Reorders the affected Overpass Mono contours so the variable font masters interpolate cleanly.
• Keeps the affected outlines geometrically unchanged.
• Regenerates mono OTF, TTF, variable, and WOFF2 outputs.

Verification

• gftools builder sources/config_mono.yaml
• python -m fontTools.varLib.interpolatable "fonts/variable_mono/OverpassMono[wght].ttf"

FontBakery note: the current upstream baseline is already red under the available WSL FontBakery environment. A local upstream-vs-change comparison during prep found no new FAIL or ERROR results introduced by the prepared changes.

Closes #100

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