Implement native text face selection

docs/platform-portability.md

@@ -31,7 +31,7 @@ or replaced before claiming portable exports.
 | AGE movie decode (`0x236` scene movies; `0x20f` modal LOGO/OP/ED) | `FfmpegMovieDecoder` is the sole factory over the project-owned `native/age_movie_ffmpeg` ABI | Windows-x64 passes the complete 213-payload installed video/audio corpus gate plus audible LOGO/OP/CHAPTER playback | Add target-specific native builds and export packaging |
 | Movie integration | Each surface owns a unique playback-instance id; `MovieRuntime` owns `IMovieDecoder` from an injected factory; video-only streams use monotonic pacing while audio-bearing streams use the Godot output clock | Concurrent/restarted uses of one asset have independent frame/audio/completion/teardown state; managed code is no longer Windows-annotated, while only the win-x64 native bundle exists today | Add Linux/macOS native builds and smoke gates |
 | Movie audio | ABI v2 returns timestamped stereo float PCM; bounded managed buffering feeds a per-playback Godot `AudioStreamGenerator` and routes native movie flags to engine buses | All 29 installed audio-bearing streams decode with signal; synchronized LOGO/OP/CHAPTER playback is audibly accepted | Treat absent, distorted, or unsynchronized audio from an audio-bearing movie as a runtime bug |
-| ADV font discovery | `godot/Main.cs` probes `C:/Windows/Fonts` for Japanese fonts | Harmless fallback today, but appearance depends on host fonts | Bundle/configure a redistributable font or add platform-specific discovery |
+| ADV font discovery/raster fidelity | Opcode `0x1a5` now reaches presentation; `godot/Main.cs` loads Windows `ＭＳ 明朝`/`ＭＳ ゴシック` from their known TTC files when available, otherwise uses the existing Japanese-font/default fallback; Godot still supplies shaping and outline synthesis | A normal Windows install now preserves Himegari's Mincho/Gothic distinction and face-specific bold caches; Linux/macOS normally lack these proprietary fonts, while advances, wrapping, boldness, and outline coverage still depend on the substitute/backend | Add configurable default and requested-face substitutions as part of the broader runtime configuration design; for portable distribution bundle licensed metric-compatible faces or define profile substitutions, then decide whether exact AGE grayscale/effect rasterization warrants a custom glyph backend |
 | Filesystem semantics | Several filename and containment comparisons use `OrdinalIgnoreCase`; installed assets are conventionally uppercase | Needs validation on case-sensitive filesystems; may hide casing or containment mistakes | Add Linux/macOS tests with mixed-case synthetic roots and use filesystem-appropriate containment rules |
 | Save/profile storage | Managed `DirectoryNativeDatStore` under Godot `user://SAVE`; native S3SD/S4SD/S3RT files and 24-bit BMP thumbnails | No Win32 path API at runtime; port saves remain isolated from the original installation | Validate replace/flush, case, permissions, and interrupted-write behavior on each export target |
 | Install/repository discovery | `engine/Age.Engine/Sys4/Paths.cs` finds `age-reimpl` above `AppContext.BaseDirectory` and assumes the current workspace sibling layout | Suitable for development, not packaged exports on any OS | Replace runtime discovery with a user-selected game root/profile; retain repository paths only for developer tools/tests |