Tectonic-Horizon: versions and changes

Revision of PR #160: removes unsupported runtime-toggle.json, falls back to defaults with a diagnostic for invalid/unreadable/oversized configuration, and fixes the GitHub formatting failure. Includes the 0.3.2 in-game settings editor and 0.3.3 upstream height adapter. Pins Horizon 8dbbde43501924d16497d251e6e9d08f812eafcd and Mixins e8cd0aa38cffef49cb2e088ef716baa107148c02. All 13 Rust tests, Clippy, formatting, native-package checking, reproducible packaging, mixin plan/apply, and the patched horizon-world compile check pass. No new interactive game test is claimed. Source: https://github.com/eltanschauung/tectonic-horizon/tree/6f69f2b64a41f0cad09f87840cbdb104138c54c3