- Remove absorb_mixins keep rule (mixin classes now renameable)
- Add mixins.rs: patch_mixins_json rewrites package + entries via
common prefix of mapped names; patch_refmap_json rewrites all strings
- Resources pass routes *.mixins.json and *refmap.json to specialized
patchers, falls back to generic text remap
Reference: OBF fabric-obfuscator patchMixinsJson/patchRefmapJson.
